单项选择题

Before the drug is used on human beings, experts have to ______ dogs.

A．be experimented
B．experiment
C．experiment with
D．experiment on

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单项选择题

Please remind me ______ be said he was going. I may be in time to see him off.

A．where
B．when
C．how
D．what

单项选择题

I can't stand ______ with Jane in the same office. She just refuses ______ talking while she works.

A．working; stopping
B．to work; stopping
C．working; to stop
D．to work; to stop

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