单项选择题

Researchers discovered that plants infected with a virus give off a gas that ______ disease resistance in neighboring plants.

A．contracts
B．activates
C．maintains
D．prescribes
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单项选择题
The government has provided the capital library with heavy ______ to keep it one of the largest in the world.
A．subscriptions
B．tips
C．subsidies
D．bonuses
单项选择题
This law ______ the number of accidents caused by children running across the road when they get off the bus.
A．intending to reduce
B．is intended to reduce
C．intended reducing
D．intends reducing
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