Giúp mình bài này vs, có lời giải chi tiết nhé (lưu ý: x là không điền mạo từ)
1 I am looking for __________ place to spend __________ night.
A. the/ the B. a/ the
C. a/ a D. the/a
2 Please turn off __________ lights when you leave __________ rooms, Venn
A. the/ the B. a/ a
C. the/ a D. a/ the
3 We are looking for a new candidates with __________ long experience.
A. the B. a C. an D. 
4 Would you pass me __________ salt, please?
A. a B. the
C. an D. X
5 Can you show me __________ way to __________ nearest station?
A. the/ the B. a/ a
C. the/ a D. a/ the
6 We have just read __________ interesting book in the national library.
A. a B. an
C. the D. X
7 You’ll get __________ shock if you touch that wire.
A. the B.
C. a D. an
8 Mr. Smith is __________ clever lawyer and __________ honest man.
A. an/the B. the/an
C. an/an D. the/the
9 __________ youngest boy of Smiths has just started going to __________ school.
A. A/X B. X /the
C. an/ X D. The/ X
10 “Do you go to __________ prison to visit him?”, asked the young woman.
A. the B. a
C. X D. an
11 __________ eldest boy Was at __________ college.
A. A/ the B. The/X
C. X /a D. An/X
12 I have a cat and a dog. __________ dog sometimes bites __________ cat.
A. A/ a B. A/ the
C. The/ the D. The/ a
13 Would you like to hear __________ story story __________ English scientist?
A. an/ the B. the/ the
C. The/ the D. The/ a
14 There’ll always be a conflict between __________ old and __________ young in a family.
A. the/ the B. an/ a C. an/ the D. the/ a
15 There was __________ Collision at __________ corner yesterday.
A. the/a B. an/the
C. a/ the D. the/the
16 Phoebe always said that this was __________ expensive shop.
A. the B. an
C. a D. X
17 Like her two sisters, Clara loves __________ crowded parties and __________ nice gifts.
A. the/a B. a/the
C. a/ a D. X/ X
18 We work 44 hours __________ months.
A. a B. the
C. an D. x
19 Our parents went to work in __________ morning.
A. a B. 
C. the D. an
20 Roger is on night duty. When we go to __________ bed, he goes to __________ work.
A. a/X B. a/ the
C. the/ X D.X/ X
mn ơi giúp mình giải có lời giải luôn nhé
A=10/56+10/140+10/260+.....+10/1400
⇔A=5/28+5/70+5/130+......+5/700
⇔3A/5=3/4.7+3/7.10+3/10.13+......+3/25.28
⇔3A/5=1/4-1/7+1/7-1/10+1/10-1/13+.......+1/25-1/28
⇔3A/5=1/4-1/28
⇔3A/5=3/14
⇔A=3/14: 3/5
⇔A=5/14
=> Đáp án B.\(\dfrac{5}{14}\)