单项选择题

--I'd like to invite you to a concert this evening.
--Thank you, but () I'll be free I'm not sure at that moment.

A．while
B．if
C．when
D．whether

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单项选择题
On()the notes proved to be forgeries.

A．inspect
B．inspection
C．inspector
D．inspecting
单项选择题
Seeing the soldiers well () for the fight, the general nodded with satisfaction.

A．prepare
B．preparing
C．prepared
D．to prepare
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