高中英语必修三第四单元重点

高中英语必修三第四单元重点、难点 Unit Four Astronomy: the science of the stars1、They were followed in time by land animals. 陆地动物及时出现。in time及时；终于A stitch in time saves nine. 小洞不补，大洞尺五。 You will get used to it in time. 最终你会习惯的。易混辨析：in time和on time in time表示“及时；终于”； 而on time表示“按时”。联想扩展：in no time 立即；马上 at one time 曾经；一度 at a time 一次 at any time 在任何时候 at times有时；偶尔 from time to time 有时即时活用： How often do you go to see your parents? - _.A. In no time B. After a while C. In a short time D. From time to time 答案：D2、They produced young generally by laying eggs. 它们以产蛋的方式生产后代。lay eggs 下蛋 How many eggs does you hen lay every week? 你的母鸡每周下多少蛋？联想扩展：lay the table 摆桌子 lay up 储存；搁置 lay over 推迟 lay the blame on 责怪 lay the foundation 奠定基础 lay to 归咎于 lay open 摊开；揭露 lay out 摆开；展示 lay aside 放在一边；积蓄 lay down 放下；放弃 lay for 等候3、These animals were different from all life forms in the past, because they gave birth to young baby animals and produced milk to feed them.这些动物和以前的任何生物形式都不同，因为它们产仔并用奶水喂养它们。give birth to生产；产生 She gave birth to a healthy baby last night. 昨晚她生了一个健康的婴儿。That century gave birth to many great men. 那个世纪产生了许多伟人。4、These animals were different from all life forms in the past, because they gave birth to young baby animals and produced milk to feed them.这些动物和以前的任何生物形式都不同，因为它们产仔并用奶水喂养它们。feed vt. 用法归纳：（1）饲养 If I am laid-off, I will feed some pigs. 如果下岗，我就养猪。Do you feed any pets at home? 你在家养宠物吗？ 特别提示：feed作“饲养”讲时，等于raise 和keep。（2）喂养 We feed grass to sheep. 我们给羊喂草。We feed sheep with grass. 我们用草喂羊。特别提示：注意feed当“喂养”讲时动物和饲料的前后顺序关系以及不同介词的用法。即时活用：1、He_ a lot of chicken_ his farm. A. rises; in B. keeps; on C. raises; in D. supports; on 2、 I have a very bad cold.- Well, have you ever heard of a saying which goes “_ a cold and starve a fever?”A. feeding B. to feed C. fed D. feed 答案：BD5、Finally about 2.6 million years ago some small clever animals, now with hands and feet, appeared and spread all over the world.最后大约在两百六十万年前，一些有手有脚的小型聪明动物出现了，并且扩散到世界各地。spread v.用法归纳：（1）传播；传开（vi.）Bad news spreads quickly. 坏消息传的很快。Word spread that there was a variant virus of H1N1. 消息称H1N1病毒已经产生变异。（2）铺开；展开(vt.) The bird spread its wings and was about to fly. 鸟伸开翅膀准备要飞。She spread a new sheet over the bed. 她给床上铺了一个新床单。（3）涂；抹(vt.) Please spread the paint evenly. 把油漆抹均匀。Its better for you to spread the honey on the bread. 你最好把蜂蜜抹在面包上。（4）伸展；延伸（vi.） Xian is spreading to the north and the west. 西安正在向北向西延伸。The forest spreads from here to the foot of Qinling mountains. 森林从这儿延伸到秦岭山脚下。联想扩展：spread out 伸开；散开；铺开 spread over 覆盖一片；持续 spread with 在上涂抹即时活用：Soon the news _ across the whole country, _the people.A. spread; exciting B. spread; excited C. was spread; excited D. was spread; exciting 答案：A6、Thus, in their turn, become the most important animals on the planet. 这样，轮到它们成为这个星球最重要的动物。in ones turn轮到某人；接着 Please get on the bus in your turn. 该你上车了。联想扩展：at every turn 事事；经常 by turns 轮流 go for a turn 散步；除去兜风 on the turn 在变质 out of turn 不合时宜的 take a turn 转弯 take turns 轮流 to a turn 恰好7、They are putting too much carbon dioxide into the atmosphere, which prevents heat from escaping from the earth into space. 它们向大气层排放大量的二氧化碳，这阻止热量向外层空间释放。preventfrom doing 防止/阻止发生 We must prevent the news from spreading. 我们应该阻止这个消息的传播。Nothing can prevent him from going away. 什么也不能阻止他离开。特别提示：(1)这个句型中prevent还可以被stop或keep替代。(2)主动句中，prevent和stop后面的from可以省略，keep后的from不能省略；被动句中三个词后的from都不能省略。联想扩展：prevent vt. 防止；预防；阻止（1） 跟名词或代词 Man is finding ways to prevent natural disasters. 人类正在寻找预防自然灾害的办法。Vitamin C is supposed to prevent colds. 据认为维生素C能预防感冒。（2）跟动名词Teachers now have no ways to prevent students listening to MP3 in class.老师们现在没办法阻止学生们上课听MP3。H1N1 flu prevented his coming to school. 甲流使他不能来上课。（3）prevention n.预防；防止 （4）preventive adj. 预防性的即时活用：1、We should do what we can to _ the Changjiang River_.A. stop; from polluting B. keep; from being polluted C. prevent; from polluting D. keep; being polluting 2、Nobody can stop the naughty boy _.A. from punishing B. being punishing C. from being punished D. to be punished 3、The heavy rain _ us starting out on time. A. kept B. prevented C. protected D. was stopped 4、It seems very difficult _.A. to stop the child to cry B. restraining the child to cry C. to keep the child from crying D. holding the childs crying答案：B C BC8、So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.所以，在未来几百万年时间里生命能否在地球上延续取决与这个问题能否得到解决。depend vi.用法归纳：（1） 依靠 We students are depending on our parents now. 我们学生现在在依靠父母。The town depends entirely upon tourism. 这个小镇主要依靠旅游。（2）依赖；指望 I mainly depended on his helping, but he didnt turn up. 我主要指望他帮忙，但是他没来。There was no bus now, so we had to depend on our legs. 现在没有班车了，我们只有指望双腿了。（3）由.决定;取决于Whether we will hold the sports meeting depends on the weather. 我们是否举行运动会取决于天气。The price depends on the quality. 价格取决于质量。特别提示：depend是不及物动词，后面一般要跟on或upon。联想扩展：It / That (all) depends. 视情况而定 即时活用：1、Im planning to hold a party in the open air, but I can make no guarantees because it _ the weather.A. links with B. depends on C. connects to D. decides on 2、The meaning of the word is various _different situation. A. depends on B. depending C. depending on D. depended on 3、 Will you go with us to the National Park? - Well, it _. A. depending B. depends C. depends on D. is depended 4、How wide is the Yellow River? That _ from where to where. A. depends B. changes C. refers D. lies 答案：BCBA9、As a result of this event, a great dust cloud formed in the sky blocking out the sunlight.这个事件的结果就是，天空形成了一团团的灰尘，遮蔽了阳光。block out vt. 封闭；遮挡 That wall blocks out all the light. 那堵墙把光都遮住了。Block out the unimportant part on the picture. 把照片上不重要的部分遮住。联想扩展：block vt.（1）堵住；阻塞A big stone has fallen from the mountain and blocked the road. 一个大石头从山上掉下来阻塞了道路。The pipe of heat must be blocked up. 暖气管子肯定是堵住了。（2）阻碍；阻挡 The wet weather blocked our plan for a trip. 下雨阻碍了我们的出行计划。The other player tried to block my advance, but he failed. 另一个球员试图阻挡我前进，但是没档住。10、Then we were off. 然后我们就出发。off(1) (和某些动词连用)开；掉 The bird flew off. 鸟飞走了。 I must dash off. 我必须马上离开。(2)（作表语）走掉；动身走 Are you really off? 你真要走吗？ I must be off now. 我必须要走。(3)（和某些动词连用）下去 Cut the end off. 把头切掉。 Mind you dont fall off. 小心别掉下去。(4)距离多远（时间；空间）Summer is only a week off. 再有一个星期就到夏天了。 They live two blocks off. 他们离我们只有两个街区。(5) 不工作；休息 The manager gave the staff a day off. 经理让员工休息一天。If you finish your work today, you can have tomorrow off. 如果你今天做完工作，我就让你明天休息一天。11、I cheered up immediately and floated weightlessly around in our spaceship cabin watching the earth become smaller and the moon larger.我立刻感到高兴，由于失重我在太空舱里飘来飘去，我望着身后的地球越来越小，而前方的月球越来越大。 cheer up 感到高兴；感到振奋Cheer up! Things are not so bad as they seem. 别泄气，事情不像看起来那么糟。 The good news has cheered him up. 12、If you are right, my mass will be less than on the earth because the moon is smaller and I will be able to move more freely.如果你正确，我的体重要比在地球上小，因为月球比地球小，这样我就能更自如活动了。mass n. 一堆；一块；一团In cold winter, the pond will become a solid mass of ice. 寒冷的冬天，池塘会变成一块坚硬的冰。I found a mass of concrete on the bed. 我在床上发现了一块水泥。联想扩展：（1）a mass of = masses of 大量的；许多After harvest, we will have a mass of rice. 收获以后，我们会有大量的水稻。 I have masses of work to do today.特别提示：a mass of = masses of 表示“大量的；许多”时，既可修饰可数名词，也可修饰不可数名词。（2） the masses 群众 The masses are the true makers of history. 人民群众是历史的真正缔造者。The party should rely on the masses. 党应该依靠群众。（3）in the mass 一般来说 The work is well done in the mass. 大体上说工作做得不错。13、Walking does need a bit of practice now that gravity has changed. 由于引力变化了，步行都需要练习。now that既然 Now that you have arrived, lets start the meeting. 既然你们到了，我们开会吧。14、After a while I got the hang of it and we began to enjoy ourselves.过了一会儿我就理解了，我们就开始尽情的玩耍。get / have the hang of 学会使用；懂得I cant get the hang of his speech. 我们有弄懂他讲演的意思。The new machine is very easy to operate, you will soon get the hang of it.联想扩展：give a hang about 对有兴趣 I dont give a hang about pop music. 我对流行音乐没兴趣。15、We watched, amazed as fire broke out on the outside of the spaceship as the earths gravity increased.我们惊奇的看着，随着地球引力的增加，宇宙飞船的外层燃烧起火。break out用法归纳：（1） 爆发 The economic crisis broke out first in the United States. 经济危机首先在美国爆发。The First World War broke out in 1914. 第一次世界大战在1914年爆发。（2）突然发生 Flu usually breaks out in winter. 流感一般发生在冬季。A big fire broke out in the factory last night. 昨晚工厂发生大火。（3）突然大声 People listening to the joke broke out laughing. 听笑话的人突然大笑起来。联想扩展：breakup 结束；拆开 break down 出故障；失败；身体垮了 breakdown打到；破坏；消除break off断开；折断；中断 break in闯入；打断；插话 break into 强行进入；打断 break through 冲过；克服；战胜 break up 驱散；分开；放假即时活用：News reports say peace talks between the two countries have _ with no agreement reached.A. broken down B. broken out C. broken