A．A more economical diesel fuel.
B．Characteristics of a new type of fuel.
C．Where is a new energy source located?
D．How to develop alternative energy sources.
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A．It will reduce the amount of pollutants in the air.
B．It will increase the amount of unpleasant odors from vehicles.
C．It will eventually destroy the ozone layer.
D．It will reduce the cost of running large vehicles.
A．it's expensive to manufacture.
B．it hasn't been adequately tested.
C．it damages car engines.
D．it's dangerous to transport.
A．help him explain the information to his roommate.
B．help him write a paper.
C．prepare for a test.
D．tell her if the notes are accurate.