相关考题
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单项选择题
I'm tired. I（）working very hard.
A.have
B.am
C.had
D.have been -
单项选择题
They（）for hours.
A.have been driving
B.have been driven
C.drove
D.drive -
单项选择题
He has（）four successful books.
A.wrote
B.written
C.been writing
