单项选择题

It can be inferred from this passage that ______.

A．the rain is caused by water-vapor
B．the higher the air rises, the higher the temperature is
C．the higher the air rises, the lower the temperature is
D．the clouds rise, and the water drops become smaller

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热门试题

单项选择题

The third paragraph is concerned with ______.

A．how clouds rise in the air
B．how rain is formed
C．why water-vapor can float in the air
D．how clouds cause rain

单项选择题

What does it of since water-vapor becomes water when it cools in Para. 3. refer to A) Water-vapor. C) Water. B) Cloud. D) Air.

A．What does "it" of "since water-vapor becomes water when it cools" in Para. 3. refer to
B．Water-vapor.
C．Cloud.
D．Water.
E．Air.