Rockets in the Sky
If someone asked you, What color is the sky? I expect that you would answer, Blue. I am afraid that you would be wrong. The sky has no color. When we see blue, we are looking at blue sunlight. The sunlight is shining on little bits of dust in the air.
We know that there is air all around the world. We could not breathe without air. Airplanes could not fly without air. They need air to lift their wings. Airplanes cannot fly very high because as they go higher the air gets thinner. If we go far enough away from the earth, we find there is no air.
What is the sky? The sky is space. In this space there is nothing except the sun, the moon and all the stars.
Scientists have always wanted to know more about the other worlds in the space. They have looked at them through telescopes and in this way they have found out a great deal.
The moon is about 384,000 kilometers away from the earth. An airplane cannot fly to the moon but there is a thing that can fly even when there is no air. This is rocket.
I am sure that you are asking, How does a rocket fly? if you want to know, get a balloon and then blow it up until it is quite big. Do not tie up the neck o f the balloon. Let go! The balloon will fly off through the air very quickly. The air inside the balloon tries to get out. It rushes out through neck of the balloon and this pushes the balloon through the air. It does not need wings like an airplane.
This is how a rocket works. It is not made of rubber like a balloon, of course. It is made of metal. The metal must not be heavy but it must be very strong. There is gas inside the rocket which is made very hot. When it rushes out of the end of the rocket, the rocket is pushed up into the air.
Rockets can fly fat out into space. Rockets with men inside them have already reached the moon. Several rockets, without men inside them, have been sent to other worlds much farther away. One day rockets may be able to go anywhere in the space.
练习:
1. What color is the sky?
A) It is blue.
B) It is white.
C) It is grey.
D) It has no color.
2. When an airplane flies too high,
A) the air will be too thin to support its wings.
B) the air will become thicker.
C) the air will exert pressure on it.
D) the air will disappear in no time.
3. A rocket can fly to the moon because
A) it looks like a balloon.
B) it is much lighter than an airplane.
C) it doesnt have wings.
D) it works like an untied balloon.
4. Which of the following statements about a rocket is NOT true?
A) It can fly when there is no air.
B) It can fly without wings.
C) It is made of strong metal.
D) It is propelled by burning gas inside it.
5. A rocket is pushed up into the air when
A) hot gas rushes out of its head.
B) it is powered by gas.
C) hot gas rushes out of its bottom.
D) hot gas rushes out of its neck.
答案: DADDC
雅思词汇中的“做加法”和“做减法”
双语盘点:如何辨别英文中的“植入广告”
学雅思词汇,迎世博
雅思词汇:轻松攻克攻略
词汇辅导:雅思高频同义词
几种构成词汇形容词的常用后缀
你不认识这些单词就落伍了
雅思词汇:废物时间法
国际知名品牌英文广告词欣赏
快乐学习雅思词汇
两会词汇:中国国家机关英文名称一览
通过AWL巧妙提高雅思词汇量
利用报纸来提高雅思词汇量
雅思词汇:国家名称
突破雅思听力;场景词汇
组合记忆雅思考试词汇 首字母规律好记忆
雅思词汇:构成形容词的常用后缀
雅思写作核心句型归纳(下)
雅思词汇的5个误解
雅思词汇:7000雅思词汇用100个句子记完!
雅思阅读之词汇考点分析
雅思同义词小汇
利用报纸提高词汇量
雅思高频词汇:社会类,动物保护类
雅思词汇:经典英文谚语集锦
雅思词汇记忆需转换思维
记忆雅思单词有妙招 20个方法帮你有效记忆
雅思生词速记:高效记忆单词方法列举
攻破雅思词汇不用词典
按场景分类识记忆雅思听力词汇
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |