V.

1. Classes begin again and everyone goes indoors.

2. The yard is very noisy until the bell rings.

3. Lan learns to use a computer in her computer science class.

4. Students take part in different activities at recess.

X:

1,English is not difficult to learn.

2,Math is not easy to learn.

3,Lan is very good at learning English.

4,How much does this book cost?

5,My brother is good at swimming.

6,There are five hundred students in that school.

7,What is your favourite subject?

8,Talking is the most activity at recess