Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1. Fortunately, I .... working alone otherwise I would have got really bored at the night shift.
A) was supposed to
B) was to
C) was used to
D) would
E) used to
2. I don't think it was a good idea to intervene, instead, you .... your child to abandon the habit of thumb-sucking gradually, all by himself.
A) have allowed
B) had allowed
C) must have allowed
D) were able to allow
E) could have allowed
3. After the voyaging ship was wrecked during a storm at sea, unfortunately, only two of the men on board .... swim to the small island nearby.
A) might
B) were supposed to
C) could
D) were able to
E) had to
4. I don't know why she didn't ask me how to do it as I ---- her.
A) must have helped
B) could have helped
C) might help
D) should have helped
E) could help
5. Martin ---- my tennis racket without asking my permission. I got really angry with him.
A) needn't have taken
B) must not have taken
C) shouldn't have taken
D) didn't need to taken
E) might not have taken
6. I don't know why Peter is so late; do you think he ---- lost coming here?
A) may get
B) could get
C) must have got
D) might have got
E) was to have got
7. What ---- to Phil? He said he ---- here at eight o'clock.
A) might have happened / will be
B) should have happened / has been
C) may happen / will have been
D) would happen / is
E) can have happened / would be
8. One of the US national security advisers ---- there ---- better intelligence sharing before the September 11 attacks.
A) had acknowledged / can be
B) acknowledges / might be
C) has acknowledged / could have been
D) acknowledged / must be
E) would acknowledge / will have been
9. We all think that Maria ---- an interesting person to meet as we ---- a lot of stories about her so far.
A) is / had heard
B) can be / heard
C) might have been / hear
D) would be / have heard
E) will be / will have heard
10. As a young woman who had never given birth before, she ---- what the experience of childbirth ---- like.
A) doesn't know / will be
B) may not know / is
C) must not have known / will be
D) may not know / would be
E) couldn't have known / would be
1. Fortunately, I .... working alone otherwise I would have got really bored at the night shift.
A. was supposed to
B. was to
C. was used to
D. would
E. used to
2. I don't think it was a good idea to intervene, instead, you .... your child to abandon the habit of thumb-sucking gradually, all by himself.
A. have allowed
B. had allowed
C. must have allowed
D. were able to allow
E. could have allowed
3. After the voyaging ship was wrecked during a storm at sea, unfortunately, only two of the men on board .... swim to the small island nearby.
A. might
B. were supposed to
C. could
D. were able to
E. had to
4. I don't know why she didn't ask me how to do it as I ---- her.
A. must have helped
B. could have helped
C. might help
D. should have helped
E. could help
5. Martin ---- my tennis racket without asking my permission. I got really angry with him.
A. needn't have taken
B. must not have taken
C. shouldn't have taken
D. didn't need to taken
E. might not have taken
6. I don't know why Peter is so late; do you think he ---- lost coming here?
A. may get
B. could get
C. must have got
D. might have got
E. was to have got
7. What ---- to Phil? He said he ---- here at eight o'clock.
A. might have happened / will be
B. should have happened / has been
C. may happen / will have been
D. would happen / is
E. can have happened / would be
8. One of the US national security advisers ---- there ---- better intelligence sharing before the September 11 attacks.
A. had acknowledged / can be
B. acknowledges / might be
C. has acknowledged / could have been
D. acknowledged / must be
E. would acknowledge / will have been
9. We all think that Maria ---- an interesting person to meet as we ---- a lot of stories about her so far.
A. is / had heard
B. can be / heard
C. might have been / hear
D. would be / have heard
E. will be / will have heard
10. As a young woman who had never given birth before, she ---- what the experience of childbirth ---- like.
A. doesn't know / will be
B. may not know / is
C. must not have known / will be
D. may not know / would be
E. couldn't have known / would be
1,Ali painted his bedroom black.it looks dark and dreary.he......................a different colour
a,had to choose b,should have chosen c,must have chosen d,could have been choosing
2,when mr.lee was younger,he.......................work in the garden for hours,but now he has to take frequent rests because he has emphysema
a,has got to b,can c,could d,should be able
3,yesterday i.....................to a furniture store.i bought a new lamp there
a,could go b,went c,could have gone d,ought to have gone
4,jimmy and marie were mischievous children they...............tricks on their teachers,which always got them into a lot of trouble
a,could play b,used to play c,could have played d,many have played
5,why are you so sure that ann didn't commit the crime she's been accused of committing?
she....................that crime because i was with her,and we were out of town on that day
a,many not have committed b,couldn't have committed
c,commited d,wasn't supposed to commit
6,since we have to be there in a hurry,we................take a taxi
a,should b,may c,are able to d,have been used to
7,it....................rain this evening.why don't you take an umbrella?
that's a good idea.may i borrow yours?
a,had better b,could be c,might d,must
8,...............you hand me that pair of scissors,please?certainly
a,may b,shall c,will d,should
9,larry drove all night to get here for his sister's wedding.he................exhausted by the time he arrived
a,ought to be b,could be c,must have been d,will have been
10,you haven't eaten anything since yesterday afternoon.
you.....................be really hungry
a,might b,will c,can d,must
11,i left a cookie on the table,but now it's gone.what happened to it?
i don't know.one of the children.....................it
a,had to eat b,should have eaten c,many have eaten d,could eat
12,what does mr.green do for a living?
nothing.he's very rich.he....................work for a living
a,must not b,shouldn't c,doesn't have to d.hadn't better
13,why are you so late?
i.....................my aunt to the airport,the traffic was very terrible
a,could take b,should take c,had to take d,must have taken
14,they towed my car away from the executive parking lot yesterday
you....................have parked there
a,may not b,should not c,must not d,might not
15,i locked myself out of my aparterment.i didn't know what to do
you.....................your roommate
a,should have called b,would have called c,may have called d,musht have called
16,barbara just told me that she can't go to the meeting tonight
she...................go!we need her there for the financial report
a,has to b,have to c,must be d,needs
17,i need some help with this table...............you lift the other and,please?
a,may b,could c,should d,shall
1.Children get present ______ Christmas and ______ their birthday. (at ... at / on ... on / on ... at / at ... on)
2. If you are going to the post off ice, would you post a letter ______ me? (to / at / on / for)
3. The windows haven’t been cleaned ______ weeks. (ago / since / for / to)
4. We usually go to our home village at least once ______ the summer. (in / on / to / for)
5. He said that John ______ u p his job.
(has given / have given / had given / had to give)
6. When I saw Susan, she said she was taking her driving test ______. (today / the next day / tomorrow / the tomorrow)
7. My TV is broken. I wish it ______ soon. (would be repaired / is repaired / was repaired / will be repaired)
8. I have lived with my parents. I wish I ______ an apartment. (will have / had / would have / has)
9. Have you ever wished you ______ to ski when you were younger? (will learn / could learn / learn / can learn)
10. Sometimes he wishes he ______ a different career when he graduates. (can choose / choose / will choose / could choose)
11. Matthew said he was meeting a friend at the station later ______. (that day / yesterday / tomorrow / this today)
12. The astronauts have alrea dy been in orbit ______ two days. (since / for / till / to)
13. We have lunch from 12.00 ______ 1.00. Then we start again go on ______ 5.30. (to ... at / from ... to / to ... to / to ... till)
14. She said that she ______ to learn to drive.
(is going / go / goes / was going)
15. She asked me ______ I liked pop music. (if / that / what / when)
16. She said that she was going away for a few days and ______ phone me when she got back. (will / must / would / shall)
17. I’ve lived in this street ______. (in 1998 / for 1 998 / since 1998 / tomorrow)
18. I want two seats for Romeo and Juliet ______ Friday night. (on / in / at / to)
19. Our train arrived in York ______ 6.00. (in / for / on / at)
20. There was an accident at the crossroads ______ midnight last night. (at / fo r / on / in)
21. She said she ______ come to the party on Friday. (won’t / doesn’t / can’t / couldn’t)
22. I’m going to swim ______ Monday with Tom. (at / on / for / of)
23. If my watch is broken, I ______ buy a new one because I always need one. (have to / might / have / may)
24. I have got an awful headache. If I see a chemist’s, I ______ buy some aspirins. (must / might / may / should to)
25. I plan to travel around the world. If I don’t visit my father in Japan this year, I ______ go to the USA. (must / have / may / ought to)
26. If you want to get good grades, you ______ study hard. (must / ought / have to/ have)
27. Let’s wait ______ it stops raining. (until / for / to / since)
28. I have lived in this house ______. (ago six years / in six years / since six years / for six years)
29. Columbus discovered America ______ the 15th century. (in / since / for / on)
30. The course begins ______ 8 am ______ 5 pm. (from ... during / from ... since / from ... to / in ... to)
31. I fell asleep ______ the movie. (during / si nce / from / for)
32. Bill asked where ______ from. (do I come / did I come / I come / I came)
33. He wonders what ______ with my heavy luggage. (I will do / I would do / will I do / I do)
34. He said that he was coming ______. (tomorrow after / yesterday / the next day / following day)
35. You ______ go to university if you want to study medicine. (has to / will / must / ought)
36. If you want to loose weight, you ______ eat too many sweets. (might not / mustn’t / shouldn’t / may not)
37. She wishes she __ ____ a new bicycle. (can have / will have / has / could have)
38. I ______ it ______ rain so much in this city. (wishes ... didn’t / wish ... didn’t / wished ... don’t / wish ... don’t)
39. If you want to get well, you ______ see a doctor. (must / might / may / ou ght)
40. ______ you ever wish you ______ fly? (Did ... could / Do ... could / Do ... can / Did ... can)
41. If he doesn’t come soon, he ______ be late. (has / ought to / ought / might)
42. I wish I ______ on a beautiful sunny beach now. (would be lying / can be lying / can be lied / could be lying)
43. ______ he will change his job if he go to the USA. (Perhaps / Since / Recently / Lately)
44. He ______ someone ______ answer that telephone. It’s been ringing for about five minutes. (wish ... can / wish ... would / wi shes ... can / wishes ... would)
45. If the kitchen is in a mess, you ______ clean it. (will / might / ought to / may)
46. I wish you ______ so fast. It makes me nervous. (weren’t driving / can’t drive / won’t drive / will not drive)
47. The music next door is very loud. I wish they ______. (would turn it down / can turn down it / will turn it down / turn down it
Underline odd words in the following paragraph.
It was a great to see you again after so long and to be able to discuss about all the things we used to do when we were students together learning english in London. I hope you had a good time journey home. Did the flight reach to Athens in time for you to get up your connection? I hope so. Do you remember I promised to send you that a book we talked about? Well, I've searched in everywhere for it but so far I haven't managed to find it. As soon as I will do, I'll put it in the post to for you - it's a really exciting story. And now I'd like to ask you about a favor, ont for me but for mys sister. She wants to have a work in Greece. She doesn't mind what she does- she would be to happy to work in a bar or to look after children. So if only you know of anything, please let us know. She'd like to spend until one year there from next January, which it should be possible. I think. She has been decided it is the best thing for her. I'm looking forward to know hearing from you soon. Give my regards to your family.
Best wishes, Costars
Choose the best answer to complete the following sentences.
1. Children get present ______ Christmas and ______ their birthday. (at ... at / on ... on / on ... at / at ... on)
2. If you are going to the post office, would you post a letter ______ me? (to / at / on / for)
3. The windows haven’t been cleaned ______ weeks. (ago / since / for / to)
4. We usually go to our home village at least once ______ the summer. (in / on / to / for)
5. He said that John ______ up his job. (has given / have given / had given / had to give)
6. When I saw Susan, she said she was taking her driving test ______. (today / the next day / tomorrow / the tomorrow)
7. My TV is broken. I wish it ______ soon. (would be repaired / is repaired/ was repaired / will be repaired)
8. I have lived with my parents. I wish I ______ an apartment. (will have / had / would / has)
9. Have you ever wished you ______ to ski when you were younger? (will learn / could learn / learn / can learn)
10. Sometimes he wishes he ______ a different career when he graduates. (can choose / choose / will choose / could choose)
11. Matthew said he was meeting a friend at the station later ______. (that day / yesterday / tomorrow / this today)
12. The astronauts have already been in orbit ______ two days. (since / for / till / to)
13. We have lunch from 12.00 ______ 1.00. Then we start again go on______ 5.30. (to ... at / from ... to / to ... to / to ... till)
14. She said that she ______ to learn to drive. (is going / go / goes /was going)
15. She asked me ______ I liked pop music. (if / that / what / when)
16. She said that she was going away for a few days and ______ phone me when she got back. (will / must / would / shall)
17. I’ve lived in this street ______. (in 1998 / for 1998 / since 1998 / tomorrow)
18. I want two seats for Romeo and Juliet ______ Friday night. (on / in / at / to)
19. Our train arrived in York ______ 6.00. (in / for / on / at)
20. There was an accident at the crossroads ______ midnight last night. (at / for / on / in)
21. She said she ______ come to the party on Friday. (won’t / doesn’t / can’t / couldn’t)
22. I’m going to swim ______ Monday with Tom. (at / on / for / of)
23. If my watch is broken, I ______ buy a new one because I always need one. (have to/ might / have / may)
24. I have got an awful headache. If I see a chemist’s, I ______ buy someaspirins. (must / might / may / should to)
25. I plan to travel around the world. If I don’t visit my father in Japan this year, I ______ go to the USA. (must / have / may / ought to)
26. If you want to get good grades, you ______ study hard. (must / ought / have / have)
27. Let’s wait ______ it stops raining. (until / for / to / since)
28. I have lived in this house ______. (ago six years / in six years / since six years / for six years)
29. Columbus discovered America ______ the 15th century. (in / since / for / on)
30. The course begins ______ 8 am ______ 5 pm. (from ... during / from ... since / from ... to / in ... to)
- 30. The course begins ______ 8 am ______ 5 pm. (from … during / from … since / from … to / in … to)
- 31. I fell asleep ______ the movie. (during / since / from / for)
- 32. Bill asked where ______ from. (do I come / did I come / I come / I came)
- 33. He wonders what ______ with my heavy luggage. (I will do / I would do / will I do / I do)
- 34. He said that he was coming ______. (tomorrow after / yesterday / the next day / following day)
- 35. You ______ go to university if you want to study medicine. (has to / will / must / ought)
- 36. If you want to loose weight, you ______ eat too many sweets. (might not / mustn’t / shouldn’t / may not)
- 37. She wishes she ______ a new bicycle. (can have / will have / has / could have)
- 38. I ______ it ______ rain so much in this city. (wishes … didn’t / wish … didn’t / wished … don’t / wish … don’t)
- 39. If you want to get well, you ______ see a doctor. (must / might / may / ought)
- 40. ______ you ever wish you ______ fly? (Did ... could / Do … could / Do … can / Did … can)
- 41. If he doesn’t come soon, he ______ be late. (has / ought to / ought / might)
- 42. I wish I ______ on a beautiful sunny beach now. (would be lying / can be lying / can be lied / could be lying)
- 43. ______ he will change his job if he go to the USA. (Perhaps / Since / Recently / Lately)
- 44. He ______ someone ______ answer that telephone. It’s been ringing for about five minutes. (wish … can / wish … would / wishes … can / wishes … would)
- 45. If the kitchen is in a mess, you ______ clean it. (will / might / ought to / may)
- 46. I wish you ______ so fast. It makes me nervous. (weren’t driving / can’t drive / won’t drive / will not drive)
- 47. The music next door is very loud. I wish they ______. (would turn it down / can turn down it / will turn it down / turn down it)
- 48. He will stay there ______ the beginning of the October. (for / to / until / on)
- 49. ______ afternoon, he feeds the chickens and collects their eggs. (The / In the / At / On)
- 50. What are you doing ______ weekend? (till this / the / in this / this)
II. Choose the answer to complete the sentence:
1. She speaks English well,. …….?
A. does she B. is she C. doesn't she D. isn't she
2. I'll try to be on time but don't worry……….. I'm late.
A. unless B. when C. as if D. if
3. "What's Linda doing?" " I'm not sure. She……….. her homework."
A. might do B. may be doing C. must be doing D. must do
4. I must hurry. My friend……...if I am not on time.
A. will be annoyed C. annoys B. will annoy D. is annoyed
5. 2 people ……..in an explosion early this morning.
A. were reported to injure B. reported to be injured C. were reported to be injured D.were reported being injured
6. Do you mind……me home
B. taking C. to take D. took A. take
7. It's high time Jack………... some work for his examination.
B. has to do C. doing D. did A. does
8. ……….air is one of the many problems we have to solve.
A. poliution B. polluted C. polluting D. pollute
9. The castle………..we visited last year was magnificent.
A. who B. where C. whose D. that
10. They arrived………… London on time.
.A. at B. on C. in D. from
11. Mai……..in Ha Noi for 3 years so far.
A. has lived B.is living C. lives D. live
12. If you have good qualifications, you will have a good……..
B. work A. vacation C. job D. holiday
13. This is the house……... Hai was born.
B. which A. where C. that D. when
14. This work need……...on time
A. finish C. finishing B. to finish D. to have finished
15. It is Saturday today,………?
A. is it B. isn't it D. wasn't it C. it isn't
16. People all love………books
D. reads A. to be reading B. reading C. read
17. It's time we………..work
. D. starting A. start B. must start C. started
18. I'd rather…………up late every morning.
D. gets A. getting B. not get C. don't get
19. My bicycle is out of order. I must………….it.
D. wash A. repair B. correct C. clean
20. Pupils inust go to class………….. time
D. into. A. by B. on C. at
Choose the correct sentence among A, B, C or D which has the same meaning as the given one
1. You must return the books by this Friday
A. The books must been returned by this Friday
B. The books have be returned by this Friday
C. The books have to return by this Friday
D. The books must be returned by this Friday
2. Barbara hasn't rung for hours
A. It is hours since Barbara last rang
B. It is hours for Barbara last rang
C. It is hours since Barbara has rung
D. It is hours for Barbara to ring
3. People say that Lan is a good student
A. It is said that Lan is a good student
B. Lan is said to be a good student
C. A and B are correct
D. Neither A or B is correct
4. He doesn't have a stylish tie and he wants to have one very much
A. He wishes to be had a stylish tie
B. He wishes that he has a stylish tie
C. He wishes he had a stylish tie
D. He wishes he will have a stylish tie
5. The last time I saw her was in 2005
A. I haven't seen her for 2005
B. I haven't seen her since 2005
C. I haven't seen her that was in 2005
D. I saw her since 2005
II. Rewrite the sentence in the same meaning:
26) Perhaps Susan know the address. (may)
Susan ..................................................may know the address......................................................
27) It's possible that Joanna didn't receive my message. (might)
Joanna ........................................................mighn't hve received my message..............................................
28) The report must be on my desk tomorrow. (has)
The report ...........................................has to be on my desk tomorrow......................................................
29) I managed to finish all my work. (able)
I .............................................................was able to finish all my work...................................................
30) It was not necessary for Nancy to clean the flat. (didn't)
Nancy .........................................didn't need to clean flat.............................................................
31) The best thing for you to do is to sit down sit down. (better)
You ..............................................................had better sit down............................................
Put the verbs in brackets into the correct tense form
1, Where...DOES JOE GO(Joe/go) with that gun in his hand? Oh, he..ALWAYS CARRIES.(always/carry)it with him when he goes walking in the woods
2,be quite!I..THINK.(think)Dad..IS SLEEPING.(sleep)upstairs.
3,I..DON'T LIKE.(not/like)cooking, but I.LOVE..(love)eating
4,Why.ARE YOU CRYING..(you/cry)?Have you hurt yourself?
5,Something.SMELLS..(smell)good.What.ARE YOU COOKING..(you/cook)?
6,In autumn the leaves..FALL.(fall)from the trees.
7,..DID YOU HEAR.(you/hear) the latest news?A bomb.WAS EXPLODING..(explode) in the station ar 10 o'clock this morning.
8,I can't find my diary.What...HAVE YOU DONE(you/do)with it?I..PUT.(put)it in your drawer last night.
9,I.SAW..(see)Steven when I was in Manchester. He..DIDN'T CHANGE.(not/change) at all.
10, She..PASSED.(pass) her degree last year, then she..GOT.(get) a job in London.
11, Gary.HASN'T BEEN..(not/be) to work since he..WON.(win) all that money.
12,I...HAVE NEVER EATEN.(never/eat) octopus,but I..ATE.(eat)squid.
13, How many times.HAVE YOU BEEN.(you/be) to the cinema this year? I ..WENT.(go) twice in January, but I.HAVEN'T BEEN..(not/be)since then.
14, When..DID PAUL AND SUE GET.(Paul anh Sue/get)married? I din't know. I.DIDN'T GO...(not/go)to their wedding.
15, Look at that! Someone.HAS LEFT.(leave)the fridge door open again! It.WASN'T..(not/be)me. I.HASN'T BEEN..(not/be)in the kitchen for hours.
16, I.HAVE JUST READ..(just/read) your composition. It's very good. How much time..HAVE YOU SPENT.(you/spend)writing it?
17,We..HAVE LOOKED.(look) everywhere for a purple silk shirt, but we..HAVEN'T FOUND.(not/find) one yet.
18,Oh,hello Debby!I'm sorry. I..DIDN'T RECOGNIZE.(not recognize)you at first. You..HAVE LOST.(lose)weight!
19,I..LEARNT.(learn) to speak a little Spanish when I was at school, but I..HAVE NEVER HAD TO.(never/have to)use it until the day I..MET.(meet) Conchita. Since that day, I ..HAVE LEARNT..(learn) a lot more.
20,Oh no!I think I.HAVE BROKEN..(break) Mim's stereo. How..DID YOU DO.(you/do) that?
21,Sally is clever. She.SPEAKS..(speak) 5 languages.
22,I don't understand those people. What language..DO THEY SPEAK.(they/speak)?
Put the verbs in brackets into the correct tense form
1, Where..is Joe going..(Joe/go) with that gun in his hand? Oh, he..always carries..(always/carry)it with him when he goes walking in the woods
2,be quite!I..think..(think)Dad..is sleeping..(sleep)upstairs.
3,I..don't like..(not/like)cooking, but I..love..(love)eating
4,Why..are you crying..(you/cry)?Have you hurt yourself?
5,Something.smells..(smell)good.What.are you cooking..(you/cook)?
6,In autumn the leaves.fall..(fall)from the trees.
7,.Have you heard..(you/hear) the latest news?A bomb.exploded..(explode) in the station ar 10 o'clock this morning.
8,I can't find my diary.What.have you done..(you/do)with it?I.put..(put)it in your drawer last night.
9,I.saw..(see)Steven when I was in Manchester. He.hasn't changed..(not/change) at all.
10, She.passed..(pass) her degree last year, then she.got..(get) a job in London.
11, Gary.hasn't been..(not/be) to work since he.won..(win) all that money.
12,I..have never eaten..(never/eat) octopus,but I.have eaten..(eat)squid.
13, How many times.have you been..(you/be) to the cinema this year? I .went..(go) twice in January, but I.haven't been..(not/be)since then.
14, When.did Paul and Sue get..(Paul anh Sue/get)married? I don't know. I..didn't go..(not/go)to their wedding.
15, Look at that! Someone.has left..(leave)the fridge door open again! It.wasn't..(not/be)me. I.hasn't been..(not/be)in the kitchen for hours.
16, I.have just read..(just/read) your composition. It's very good. How much time.did you spend..(you/spend)writing it?
17,We.have been looking..(look) everywhere for a purple silk shirt, but we.haven't found..(not/find) one yet.
18,Oh,hello Debby!I'm sorry. I.didn't recognize..(not recognize)you at first. You.have lost..(lose)weight!
19,I.learned..(learn) to speak a little Spanish when I was at school, but I.never had to..(never/have to)use it until the day I.met..(meet) Conchita. Since that day, I ..have learned..(learn) a lot more.
20,Oh no!I think I.have broken..(break) Mom's stereo. How.did you do..(you/do) that?
21,Sally is clever. She.speaks/can speak..(speak) 5 languages.
22,I don't understand those people. What language.do they speak..(they/speak)?
1. b
2. b
3. a
4. b
5. b
6. a
7. c
8. c
9. a
10. b
11. b
12. b
13. c
14. c
15. b
16. b
17. c
18. c
19. b
20. c
21. b
22. b
1. - Is Jeff a good student?
- He . I don't know him well, but I heard he got a scholarship for next year.
a. must be b. could be c. is
2. - Do you know where Eva is?
- She at Barbara's house. She said something about wanting to visit after work today, but I'm really not sure.
a. must be b. could be c. is
3. - I stayed up all night finishing this report for the boss.
- You really tired.
- I do.
a. must feel b. might feel c. feel
4. - Where's the leftover chicken from dinner last night?
- I just saw it when I got some ice cubes. It in the freezer.
a. must be b. might be c. is
5. - It's supposed to rain tomorrow.
- I know, but the forecast wrong. Weather forecasts are far from 100 percent accurate.
a. must be b. could be c. is