— I called you at ten but there was no reply. —Oh that was probably when I a shower. A.

问题补充：

— I called you at ten, but there was no reply.

—Oh, that was probably when I a shower.

A. am taking

B. took

C. were to take

D. was taking

答案：

A. am taking

B. took

C. were to take

(答案→)D. was taking

解析：意为：“你打电话来时，我可能正在洗淋浴”。指在过去某个时候正在发生的动作，用过去进行时。