— When do you usually take a walk?— the morning.A. InB. OnC. AtD. For

问题补充：

— When do you usually take a walk?

— the morning.

A. In

B. On

C. At

D. For

答案：

(答案→)A. In

B. On

C. At

D. For

解析：句意：你通常什么时间散步？在早晨。通常说“在早晨”用介词in；故选A。