II, 

1. My brother speaks English worse than my sister.

2. Because of laziness, she didn't pass the exam.

3. This homework can be done easily by me.

4. Hoa fancies reading books in her free time.

5. If Thu didn't eat much chocolate, she would not be very fat.

III.

1. While Mary was playing basketball in the park, she fell over.

2. She hasn't studied French for ten years.

3. If I were you, I would invite Jack to the party.

4. Vocanoes in Iceland don't erupt very often.

5. The United States is the third largest country in the world.

Xin hay nhất ạ

=>
5. Air pollution is a serious problem in many cities.
II/
1. My brother speaks English doesn't as well as my sister.
2. Because ò fbeing lazy, she didn't pass the exam.
3. This homework can be done easily.
4. Hoa fancies reading books in her free time.
5. If Thu didn't eat much chocolate, she wouldn't be very fat.
III/
1. While Mary was playing basketball in the park, she fell over.
2. She has not studied French for ten years.
3. If I were you, I would invite Jack to the party.
4. Volcanoes in Iceland don't erupt very often.
5. The United States is the third largest country in the world.