单项选择题

Crew chiefs supervised engines, switches and lights that told them how each item of equipment was functioning.

A．observed
B．preserved
C．monitored
D．nurtured
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单项选择题
Peter was seen crying when he came out of the office. We can deduce that he must have been punished.
A．confer
B．refer
C．prefer
D．infer
单项选择题
They demand to set up an organization flexible enough to cope with any emergency.
A．portable
B．valiant
C．trivial
D．mobile
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