单项选择题

A．that CFC manufacture is completely forbiddenB．that th……

The best way to save ozone is ______.

A．that CFC manufacture is completely forbidden
B．that the production of CFC is reduced
C．to find substitutes for CFCs
D．to reduce the danger of CFCs

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热门试题

单项选择题Why should governments ensure tire careful handling and recycling of the CFCs now in use

A．Because the CFCs directly damage the people's health.
B．Because the CFCs are poisonous chemicals.
C．Because the production of the CFCs costs a lot.
D．Because the CFCs can attack ozone by liberating atoms of chlorin

单项选择题At first, locomotives could not popularize themselves because they ______.

A．could not bring profits or save much labor
B．attract people
C．only caught some people's interest
D．were not welcome

单项选择题The multi-tube boiler system made the Rocket, Robert's locomotive,______.

A．powerful
B．achieve a speed of 30 miles an hour
C．acquire 25 little tubes
D．good for hauling trains

单项选择题According to the passage, what do student researchers often learn when they discuss their work in class

A．Other students rarely have objective comments about it.
B．Other students do not believe the researchers did the work themselves.
C．Some students feel that the conclusions are too obvious.
D．Some students do not understand the meaning of the researchers’ questions.

单项选择题According to the passage, what is one major criticism students often make of published research

A．The research has been done in unimportant fields.
B．The researchers did not adequately establish the relationships involved.
C．The researchers failed to provide an appropriate summary.
D．The research has not been written in an interesting way.