1.He came in.I was working in the gảden
-When he came in, I was working in the garden
2.Why didn't you help him?
-Why didn't you give him a hand?
3.Jenny cleaned the house and then she met her frirnds
-Before meeting friends, Jenny had cleaned the house

4.I last went to the zoo 2 year ago
-I haven't gone to the zoo for 2 years
5.Mary often read interesting books on the weekend
-Interesting books are often read by Mary on the weekend
6.Tom went to the hotel.The receptionist went out
-By the time Tom went to the hotel, the receptionist had gone out
7.Tom is a more beautiful dancer than Paul
-Paul dances less beautifully than Tom does
8.You for got locking the door,didn't you?
-You didn't remember locking the door, did you?

câu 8. remember to lock (remember + to-V: nhớ phải làm gì đó, remember + V_ing: nhớ đã làm việc gì đó trong quá khứ)

B

B

B

A

If she weren't very busy, she could help us 

It's two months since i last met him

Lan's mother is better at cooking than her

1.If she weren't busy,she could help us

2.It's two months since I last met him

3.Lan's mother can cook better than her

1. If the we have more cars, air pollution in our city will become worse

2. The victims were provided with food and water by the rescue team

3. Because of the polluted environment, many new diseases have appeared

If I were you, I would go there alone. 

1. A.'tropical   B.di'saster   C.'damage   D.'chemical

2. A.pol'lution   B. contami'nation   C.des'troy   D.en'vironment