I/

1. If Linh recycles papers, she will save a lot of trees

2. We should try to recycle old paper

3. Don't throw plastic beacause you can reuse them.

II/

1. If people use reusable bags, they will help protect to the enviroment

2. Sweden is a country in northern Europe

3. England tower is the most famous in it

III/

1. he has never went abroad before

2. The last time I saw him was 8 days ago.

3. How long have you had it?

IV/

1. If we pollute the river, a lot of fish will die

2. My little brother can ride a bike, but he cannot swim

3. The yellow car is more expensive than red one