阅读理解。
What is the sky? Where is it? How high is it? What lies above it? These questions are difficult to answer,
aren't they?
Is the sky blue? The sky has no colour. We know that there is air around the world. When the planes fly,
they need air to lift their wings. Planes can not fly very high because when they go higher, the air gets thinner (薄的). If we go up about 1,200 kilometers from the earth. We find there is no air.
Perhaps we can answer some of our questions now. The sky is space (太空). In the sky there is only the
son, the moon and all the stars.
1. What is the sky?
A. It's the clouds.
B. It's space.
C. It's air.
D. It's nothing.
2. The sky _______.
A. is blue
B. is white
C. is black
D. has no colour
3. Planes can not fly very high because _______.
A. the air becomes thinner.
B. the air becomes thicker.
C. the flying machine is not good.
D. the flying machine is bad.
4. If we go up about 1,200 kilometers from the earth, we find _______.
A. there are more air
B. there is air
C. there is nothing but air
D. there is little air.
5. In space there is _______.
A. nothing
B. air everywhere
C. anything
D. only the sun, the moon and all the stars.