问题
She has some trouble _____ out the math problem.
A:work
B:to work
C:working
D:Works;
B:to work
C:working
D:Works;
正确答案是：
同类题型
I can’t find my watch. But it must be _____ in this room.
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_______ you’ve got a chance, you might as well make full use of it.
Mr.Green teachescomputerscience.
When I got back home I saw a message pinned to thedoor ______“Sorry to miss you; will call later.”