—Why didn’t you answer the phone when I called you last night?—Sorry I a bath upstairs.

问题补充：

—Why didn’t you answer the phone when I called you last night?

—Sorry, I a bath upstairs.

A. am having

B. have

C. was having

D. had

答案：

A. am having

B. have

(答案→)C. was having

D. had

解析：考查时态。过去进行时表示在过去某一时刻或某一段时间内进行或发生的动作。这里表示昨天打电话的时候我正在做某事。句意：——昨晚我打电话的时候你为什么不接电话？——对不起，我正在楼上洗澡的。故C正确。