用所给词的适当形式填空。

1. Half the boys in my class ______ (like) playing basketball.

2. The mother asked his son ______ (not ride) too quickly on the way to school. It's dangerous.

3. If you exercise every day, you ______ (be) healthy.

4. What will happen if Lucy ______ (bring) her friends from other school to the party?

5. He is a difficult man ______ (communicate) with.

毕脱斑的形成是因为（）。

A.维生素A摄入过量

B.核黄素缺乏

C.体内脂质过多

D.硫胺素缺乏

E.维生素A摄入不足