问题 选择题
—Why,I didn’t get you on the phone.
—We ________football on the playground when you phoned.
A.must be playing
B.must play
C.must have played
D.must have been playing
答案

D

解析 句意为:——嗨,我打电话没找到你。——你打电话的时候我们肯定正在操场上踢足球。表示对过去所发生的事情的肯定推测用must have done的形式,再结合语境可知此处推测的是过去某个时间正在发生的事情,故用must have been doing,故答案为D项。

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