--- Whose backpack is this?--- It        be Mary’s. She is looking for hers.
#74249
A
can
B
must
C
may
D
can’t
推荐题目
He ______ it on schedule, but somehow he fell behind.
#62908
A
must have done
B
might finish
C
could have finished
D
could finish
I told Sally how to get here, but perhaps I ___ for her.
#63323
A
had to write it out
B
must have written it out
C
should have written it out
D
ought to write it out