Question

— Why! I _____ get you on the phone.
— We ______ basketball on the playground when you phoned.

A．didn't; must be playing

B．couldn't; must be playing

C．couldn't; must have played

D．didn't; must have been playing

Answer 1

D

解題的關鍵在第二空。must be doing表示對目前下在發(fā)生的情況的推測，而根據題干的時間提示… when you phoned，可知是談虎色變論過去情況，因此排除A、B現(xiàn)兩項。must have done 表示對過去已經發(fā)生的行為進行推測；must have been doing表示對過去正在進行的動作推測。句意：你打電話來的時候，我們一定在在操場打藍球呢。由此判定答案為D。