Science has told us too much about the moon that it is fairly easy to imagine what it would be like to get there. It is certainly not a friendly place. Since there is no air or water, there can be no life of any kind. There is not much variety of scenery either. For mile after mile there are only flat plains of dust with mountains around them. Above, the sun and stars shine in the black sky. If you step out of the mountain shadow, it means moving from the severe cold into intense (强烈的) heat. These extreme temperatures continually break rocks away from the surface of the mountains. The moon is also a very silent world, for sound waves can only travel through air. But beyond the broken horizon, you see a friendly sight. Our earth is shining more brightly than the stars. From this distance, it looks like an immense (巨大的) blue, green and brown ball.
The moon is an unfriendly place because                   .

A．there is no air, no water, no life, no scenery	B．the sun and stars shine in the sky
C．temperature breaks rock away	D．all of the above

Without           , the moon is a silent world.

A．man

B．air

C．sound

D．water

According to the passage we know that             .

A．the earth looks like a colored ball

B．we can enjoy the scenery on the moon

C．every inch of the moon is very hot

D．the extreme temperature breaks rocks away from the surface of mountains

We can conclude（断定） that “continually” means          .

A．sometimes

B．always

C．without break

D．frequently

The best title for the passage is                        .

A．An Unfriendly and Friendly Place	B．The Geography of the Moon
C．Moon, a Silent World	D．The Moon