赞题库-背景图
单项选择题

I slipped and fell while I______.

A．
[A] am cleaning windows

B．
[B] clean windows

C．
[C] was cleaning windows

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热门试题

单项选择题______Lily______ I have been to the Great wall.

A．
[A] Either; or

B．
[B] Neither; nor

C．
[C] Both; and

单项选择题Great changes______ place since he left here.

A．
[A] have been taken

B．
[B] have taken

C．
[C] were taken