单项选择题

What is the advantage of the new air-conditioning system

A．The cost of the air-conditioning device is very low.
B．The working principle of the system is simple.
C．Minimal amount of energy is needed.
D．Only natural resources can be made use of.

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热门试题

单项选择题

The new idea the passage presents us is about ___________.

A．designing a new type of heat exchanger
B．storing winter cold for use in summer
C．establishing an underground air-conditional system
D．creating an efficient and economical air-conditioning system

单项选择题

It can be inferred from the passage that on other planets

A．there is no oxygen for creating life
B．there is no suitable temperature for creating life
C．living things of different kinds may exist
D．living things similar to that on earth may exist