Without gravity, we _____ walk on the ground as freely as we do now. 
#63085
A
couldn’t
B
mustn’t
C
shan’t
D
needn’t
推荐题目
---- Did you pass the driving test? ---- No. I ______ it, but I had little time practicing.
#63236
A
could have passed
B
must have passed
C
can’t have passed
D
shouldn’t have passed
I__________through that bitter period without your generous help.     
#63620
A
couldn’t have gone
B
didn’t go
C
wouldn’t go
D
hadn’t gone