(             )1.Sweet snacks give us energy, _____________ they are not healthy.

A. because         B. but                    C. so                     D. after

(             )2._______________ do you swim every day? I swim for half an hour.

A. How long          B. How often  C. How much D. How many

(             )3.Coke is not good ____________ children. You should not ask your son to drink it.

A. to                     B. by                     C. for                    D. in

(             )4.Millie doesn’t walk_______________ school, she walks _______________ home.

A. to/to                 B. 不填/不填 C. to/不填             D.不填/to