问题
Where is Bob? I cannot find him anywhere. — He _____have been off long. I heard him make a call just now.[ ]
A: shouldn't
B: can't
C: mustn't
D: needn't
B: can't
C: mustn't
D: needn't
正确答案是：
同类题型
It’s only ten minutes’ walk; I could have got there on foot— YesA taxi _______ not at all necessary
I__________to come over to see you last night，but someone called and I couldn’t get away
Well, I do think the iPod is a smart, convenient and intelligent. —_____.
The bell ________ the end of the period rang,________ our heated discussion. [ ]