单项选择题

The ratio of the work done by the machine ______ the work done on it is called the efficiency of the machine.

A．against
B．with
C．to
D．for
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单项选择题
The work they are doing is ______ great value.
A．in
B．of
C．by
D．from
单项选择题
I regret ______ the novel to Jim because he made it very dirty.
A．to lend
B．having lent
C．to be lending
D．lent
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