22.--- I called you last night,but nobody answered the phone.

问题描述:

22.--- I called you last night,but nobody answered the phone.
--- Sorry,________.
A.I must be sleep at that moment.B.I must have slept at that moment.
C.I must have been asleep at that moment.D.I must have fallen asleep at that moment.

选C.我不同意一楼的回答.题目中的他没听电话,肯定是因为他睡着了.C和D的区别就是asleep和fall asleep 的不同.
意思都是入睡但fall asleep强调入睡的动作
be asleep 强调睡着的状态
例如:The baby is asleep,don't turn up the radio.
My father was so tired that he fall asleep quickly.
所以选c更好,因为强调他睡着了,而不是D已经在入睡这个动作