It's impossible for a child to do so much
问题:
It's impossible for a child to do so much work within a short period of time, ______
A. isn't it
B. is it
C. has it
D. hasn't it
It's impossible for a child to do so much work within a short period of time, ______
A. isn't it
B. is it
C. has it
D. hasn't it
A.①②③
B.②③④
C.①③④
D.①②③④
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