问题补充：
---I called you yesterday evening, but there was no answer.
----- Oh, I’m sorry. I dinner at a restaurant at that time.
A. have
B. had
C. was having
D. have had
答案：
A. have
B. had
(答案→)C. was having
D. have had
解析：句意：我昨晚给你打电话，但是没人接。对不起，我当时在参观吃饭。用过去进行时，表示过去某个时间正在进行的动词，结构为was/ were+doing；故选C。
