内容发布更新时间 : 2024/5/19 22:44:43星期一 下面是文章的全部内容请认真阅读。

Unit 4 Astronomy:the science of the stars

Period 2 知识讲练课

学习目标

1.Master the usages of such important words and expressions as:exist,puzzle,in time,in one’s turn,prevent...from,cheer up,break out,watch out;learn to express yourself by using them.

2.Learn the method of constructing knowledge trees through self-study and cooperative exploration.

3.Enjoy the fun of expressing yourself by using English and participate in class with a strong passion.

课堂探究

一、词汇精粹

学习建议:根据所列例句,理解并尝试总结下列词汇的用法。 1.exist vi.存在;生存

【教材原句】 They laid eggs too and existed on the earth for more than 140 million years.它们也生蛋,在地球上生存了一亿四千多万年。

【观察思考】

(1)Fish can’t exist out of water.鱼离开了水无法生存。

(2)Do you believe the existence of ghosts?Perhaps they only exist in some people’s imagination.

你相信鬼魂的存在吗?或许他们只存在于一些人的想象里。

(3)The hostages (人质)existed on bread and water.人质靠水和面包生存。

(4)There exist many ancient temples of this kind on the shores of the Mediterranean. 在地中海沿岸地带,有许多这样的古庙。

(5)As time went on,the small town came into existence. 随着时间的流逝,这个小城镇形成了。 exist vi.存在;生存 (1)存在于…… (2)靠……为生 (3)某地存在…… (4)开始存在;成立 2.puzzle n.谜;难题 vt.&vi.(使)迷惑;(使)为难 【教材原句】 How life began on earth is one of the biggest puzzles that scientists found hard to solve.地球上的生命是如何起源的是科学家们最难以解答的问题之一。

【观察思考】

(1)What puzzles me was why they didn’t take her advice. 使我大惑不解的是他们为什么没有接受她的建议。 (2)They puzzled over the question for quite a while. 这问题他们苦苦思索了很久。

(3)The present situation is puzzling,and we are all puzzled about what will happen in the days to come.目前的形势令人困惑,我们都对未来几天将会发生什么感到困惑。 (1)puzzle over

1

(2)对……迷惑不解 (3)puzzling adj. (4)puzzled adj. 二、短语集锦

1.in time 及时;终于

【教材原句】 They were in time to produce carbon dioxide,nitrogen,water vapour and other gases,which were to make the earth’s atmosphere.它们最终产生了碳、氮气、水蒸气和其他多种气体,从而形成了地球的大气层。

【观察思考】

(1)You are lucky to be in time for our party.你很幸运能及时参加我们的聚会。 (2)He made it in time when he failed thousands of times. 当失败了成千上万次后,他终于成功了。

【联系拓展】(1)He could not come on time because of the traffic jam. 因为交通堵塞,他不能准时(按时)到了。

(2)At no time should we give in to difficulties.我们在任何时候都不能向困难屈服。 (3)The bus was filled with students in no time.这辆公共汽车很快就被学生挤满了。 (1)in time (2)按时;准时 (3)立即;马上 (4)从不;绝不 2.in one’s turn轮到某人;接着

【教材原句】 Thus they have,in their turn,become the most important animals on the planet. 于是,它们接着成为了这个行星上最重要的动物。 【观察思考】

Now that I have finished buying,Tom,in his turn,should cook. 既然我已经完成了采购,就该轮到汤姆来做饭了。 【联系拓展】

(1)We protect the environment and in turn it benefits us a lot. 我们保护环境,反过来保护环境会使我们受益匪浅。

(2)The children called out their names in turn.孩子们依次自报姓名。 (3)We took turns to drive the car on the way. 在路上我们轮流开车。

(4)It is your turn to do the experiment.轮到你做实验了。 (1)反过来,转而;依次;轮流;逐个 (2)轮流做…… (3)轮到某人做某事 3.prevent...from...阻止;制止 【教材原句】 They are putting too much carbon dioxide into the atmosphere,which prevents heat form escaping from the earth into space.

他们把过多的二氧化碳释放到大气层中,这使得地球上的热不能释放到太空中去。 【观察思考】

He said this would prevent companies from creating new jobs. 他说这将阻止各公司创造新的职位。

2

【联系拓展】

(1)We should try our best to stop the West Lake (from)being polluted. 我们应该尽力阻止西湖被污染。

(2)We’ll be prevented / stopped / kept from finishing our experimental programme. 我们将被阻止完成实验性项目。

阻止……干某事: (1) (2) (3) 4.cheer up感到高兴;感到振奋;使高兴起来

【教材原句】 I cheered up immediately and floated weightlessly around in our spaceship cabin watching the earth become smaller and the moon larger.我立刻感到很高兴,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。

【观察思考】

(1)Cheer up! Our troubles will be over soon.振作起来!我们的困难很快就会过去。 (2)When I’m feeling sad my mother tells me funny stories to cheer me up. 当我感到忧伤时,我的母亲就会给我讲有趣的故事让我高兴起来。

【联系拓展】 We did our best to cheer him on when he was about to give up. 当他将要放弃时我们尽力鼓励他。 (1)(使)感到高兴;(使)感到振奋 (2)(赛跑比赛中)以喝彩声鼓励某人;为某人加油 (3)cheerful adj. 5.break out (火灾,战争,疾病)突发,爆发

【教材原句】 We watched,amazed as fire broke out on the outside of the spaceship as the earth’s gravity increased.我们惊奇地看着,随着地球的引力增加,宇宙飞船的外层燃烧起火。

【观察思考】

He was 29 when the war broke out.战争爆发时他29岁。 【辨析】 break out/take place/happen

意为“发生、爆发”,常指战争、灾难、疾病或者争吵等事件的发生,也可以表示突然大声叫喊等。

指某事按照计划进行或者按照计划发生,此外还有“举行”之意。 一般用于偶然或突发性事件。

(1)The party will take place on Sunday,rain or shine. 不管下雨还是阳光明媚,聚会将在周日举行。

(2)The plane crash happened only minutes after take-off.飞机起飞几分钟后就坠毁了。 【联系拓展】

逃脱;脱离 出故障;垮掉 强行进入;打断 强行闯入;突然开始 断开;中断;停顿 突破;冲破

破碎;解散;分手

(1)They broke away from the national union and set up their own organization.

3