《2025年练习部分八年级英语上册沪教版54制》

3 Read the online article. 阅读网络文章。
Why do stars twinkle (闪烁) at night?
Did you ever wonder why stars twinkle at night?
It's interesting to know that stars themselves don't actually twinkle. They seem to twinkle because of the Earth's atmosphere (大气层).
When light moves from one type of air to another, it bends (弯曲). This bending is called refraction (折射). Refraction happens because light changes speed when it moves between materials of different densities (密度), like going from air into water.
So, how does refraction connect to twinkling stars?
The Earth's atmosphere has many layers with different temperatures and densities. When light from a star passes through the air, it gets refracted many times. Some light rays move straight to us, while others bend away. It happens very fast and creates the twinkling effect.

Have you noticed that stars near the horizon (地平线) twinkle more than those overhead? It's because you're looking through more layers of the Earth's atmosphere in that direction and it means the light goes through more refraction. So, the next time you're watching the twinkling stars, you'll know it's all thanks to the atmosphere's bending light show!
3-1 Choose the best answer. 选择最恰当的答案。
(1) Why do stars appear to twinkle?
A. Because they are moving fast.
B. Because they are actually twinkling.
C. Because the starlight travels through the Earth's atmosphere.
D. Because the light from the Sun sometimes hides them.
(C)
(2) How does the Earth's atmosphere influence the light from stars?
A. By strengthening (增强) the light.
B. By causing the light to bend.
C. By taking in the light.
D. By changing the light's colour.
(B)
(3) Where do stars appear to twinkle more?
A. In the city centre.
B. In space.
C. Directly overhead.
D. Near the horizon.
(D)
3-2 Complete the sentences. 补全句子。
(1) Refraction happens because light changes speed when it moves between materials of different densities.
(2) When light from a star passes through the air, it will get refracted many times.
(3) If you are on the moon, can you see the stars twinkling?
□ Yes, I can. □ No, I can't.
My reason: Because the moon does not have an atmosphere like the Earth./Because there's no refraction.
3-3 Think and write down your ideas. 思考并写下你的想法。
Do you think human's curiosity about space is important? Why or why not? Write your opinion and give a fact.
Opinion: Human's curiosity about space is important because it helps us discover new things in space.
Fact: Scientists all around the world keep exploring other planets. So far, humans have stepped on the moon, built space stations and made many new discoveries.

答案： 3-1.
(1) C
(2) B
(3) D
3-2.
(1) light changes speed
(2) get refracted many times
(3) No, I can't. Because the moon does not have an atmosphere like the Earth./Because there's no refraction.
3-3. (Answers may vary.) Opinion: Human's curiosity about space is important because it helps us discover new things in space. Fact: Scientists all around the world keep exploring other planets. So far, humans have stepped on the moon, built space stations and made many new discoveries.