—What are you doing for your vacation?—.A. I’m going hiking.B. I went to the beach.C. I of

问题补充：

—What are you doing for your vacation?

—.

A. I’m going hiking.

B. I went to the beach.

C. I often go to the mountain.

D. I like going bike riding.

答案：

(答案→)A. I’m going hiking.

B. I went to the beach.

C. I often go to the mountain.

D. I like going bike riding.

解析：本题的问句是进行时态的结构表示将来，回答语也应该使用此结构be+doing，故选A。