问题补充:
—I phoned you at 9 this morning but got no answer.
—I am sorry. I the bell. I in the garden.
A. didn’t have heard, must have been
B. didn’t have heard, must be
C. didn’t hear, must have been
D. didn’t hear, must be
答案:
A. didn’t have heard, must have been
B. didn’t have heard, must be
(答案→)C. didn’t hear, must have been
D. didn’t hear, must be
解析:情景对话句意为:--今天早上九点我给打了个电话不过没人答复
--很抱歉。没有听见电话声。我那时一定在花园吧
一般过去时:简单陈述一件过去发生的事,强调事件本身。Must have done 是must对过去事件的肯定推测,这个事件肯定发生了,所以用完成时。结合语境可知,选C.