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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On ()the notes proved to be forgeries.

A.inspect
B.inspection
C.inspector
D.inspecting
单项选择题
Come and see me whenever ().

A.you are convenient
B.you will be convenient
C.it is convenient to you
D.it will be convenient to you
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