2. The sun and ____________ planets are called_______________. eight / its the solar system

3. The earth goes around the sun, and _______ other planets _____________ the sun, too. seven go around

4. There has been life on the earth for _______________________ ( 数亿 )years. hundreds of millions of But we have not ________( 找到 ) life on ___________( 其他任何 ) planets yet. found any other

5. But our solar system is only a small part of _______________________( 银河系 ). the Galaxy / the Milky Way Our solar system is only _________________ ( 一小部分 )the Galaxy. a small part of

6. galaxies Scientists have discovered many other _________ in the universe. But they are very ____________ so their light has to travel for many years to ______( 到达 ) us. far away reach

7. It’s _________ to __________ how big the universe is ! (We don’t know how big the universe it.) impossibleimagine

8. ___________( 为了 ) get more information _____ ( 关于 ) the space, scientists have sent spaceships to Mars _______________( 拍照 ). In order to on to take photos (to do sth 表示目的 )

9. However ， no spaceship has travelled ____________( 足够远 ) to reach other stars in our Galaxy. far enough

10. 1. 成百万年 2. 在其它的行星上 3. 绕太阳转 4. 他们中没有一个 5. 一小部分 6. 在宇宙中 7. 距离好远 8. 足够远 9. 如此多 10. 和某人联系 millions of years on any other planets go around the sun none of them a small part of in the universe far away far enough so many communicate with sb.

11. Scientists think that there has been life on the earth for hundreds of millions of years. However, we have not found life on any other planets yet. 在地球上 成百上千 数百万亿万 Let’s know the passage better.

12. The earth is a planet and it goes around the sun. Seven other planets also go around the sun. None of them has anNone environment like that of the earth, so scientists do not think they will find life on them. The sun and its planets are calledthat the solar system, and our solar system is a small part of a much larger group of stars and planets, called the galaxy or the Milky Way. There are billions of stars in the Galaxy, and our sun is only one of them. 绕着转 它们中没有一个 be called 被叫做 太阳系 一小部分 一个大的多的星群 银河 几百亿 … 之一 none of … 表示（三个以上） 一个也没有。做主语时，谓 语动词可用单数或复数

13. Scientists have also discovered many other galaxies in the universe. They are very far away and their light has to travel for many years to reach us. So how harge is the universe? It is impossible to imagine. 在宇宙里 不得不 这简直无法想象 It is +adj for sb. to do sth. reach =arrive at/ in+ 地点 =get to Scientists have sent spaceships to the planet Mars to take photos. They have even sent spaceships to travel outside the solar system. However, no spaceship has travelled far enough to reach other stars in our Galaxy.far enough send sth to sp. 发送 … 到拍照片 太阳系 adj./ adv enough to do sth 足 够做某事

14. Scientists have always asked the questions: with so many stars in the universe, are we alone, or is there life out there in space? Have there been visitors to the earth from other planets? Why has no one communicated with us? We do not know the answers…yet. with + 名词 + 介词短语，表示伴随情况，意思是 “ 有 ……” 。 在太空中 其他行星 没人 no one 表示 “ 没有人 ” ，作主语时，谓语动词常用单数形式。 communicate with sb. 与 … 联系 / 交流 Listen and read the passage.

15. 注意： none 与 no one （ nobody ） 的区别： (1)none 既可指人也可指物，通常与表范围的 of 短语连用； no one(=nobody) 只能指人，不能与 of 短语连用。 如： _________ of the reasons was true. A. None B. No one C. All (2) none 与数量有关，可回答 how many 问句，表示 “ 一个 也没有 ” ；而 no one 表示 “ 什么人也没有 ” ，可回答 who 问句。 如 ： -Who are you speaking to?-_________. -How many students are there in the room? -_________. A No one None

16. that 是指示代词。为避免重复，可用 that 或 those 来 代替前面已提到过的人或事物； 1.The air in the countryside is fresher than _________in the city. 2.The streets in the city are wider and the buildings are taller than ________ in the county. 3.The environment is much cleaner than ________ in the city. that those that

17. 2. However, no spaceship has traveled far enough to reach other stars in our Galaxy. 然而，没有一个航天器去到足以 到达我们银河系其他恒星那么远的地方。 …enough… to do adj./ adv. + enough + to do sth. 足够 … ，可以 … not + adj./ adv. + enough + to do sth. 不够 … ，不可以 … (1) 我们有足够的钱花。 We have ___________________________. (2) 他跑得够快，很快追上了我们。 He ran __________________ catch up with us soon. (3) 他年龄不够大，照顾不了自己。 He _______________________________________. enough money to spend fast enough to isn’t old enough to look after himself

18. Look at the picture from a science story for children and answer the questions.

19. 1. What can you see in the picture? aliens a dog soft chair umbrella the earth the sea strange machine

20. 2. Can we see the earth from Mars? 3. What color is the earth? We can see the earth from Mars. It looks blue.

21. 4. Are the aliens the same as us? No. They are different from us. 5. What color are they? They are green all over.

22. 6. What are the aliens doing on Mars? Some are … and some are… 7. Are they living a happy life there? Yes, they are very happy there.

23. What have the scientists just received? (a message from one of our spaceships) They have just received a message from one of our spaceships. 1. Where has the spaceship landed? (Mars) It has landed on Mars. 2. What has the spaceship discovered? (people on Mars) 3. Why have the people on Mars not sent us a message? (do not know how to) It has discovered people on Mars. They do not know how to send us a message. They do not know how to visit us on the earth. 4. Why have the people on Mars not visited us on the earth? (do not know how to)

24. We have just received a message from our spaceship to Mars. Our spaceship has discovered aliens there. They have never sent us a message because they don’t know how to communicate with us. They have not visited the earth because they don’t know how to fly to our planet, and they prefer life on Mars. They seem very happy on their planet. They have used parts from the other spaceships from the earth to make TVs, radios, etc. We hope they don’t do the same with this one.

25. Homework 1. Revise the language points of unit 2. 2. Recite the text. 3. Do exercises of M3U2 in your WB.