assure、ensure、insure用法比较和one用法ppt课件

1、once的用法,Once will have to do. You can go just this once. 必须去做一次，你只去这一回一次。 Once is enough for me. 对我来说一次就够了。,1.n. 发生一次；一次：,2.adj.曾经的；以前的,a once friend 从前的一个朋友 the once capital of the nation. 该国以前的首都,3.conj.,(1).once作连词时，意为“一旦就”，用于连接时间状语从句，相当于as soon as。如： Once he goes, we can clean up.他一走，我们就能清理 (2).

2、一旦,一经.便Once you get into a bad habit, youll find it hard to get out of it. 一旦染上坏习惯,想改掉就难了 Once you begin you must continue.你一旦开始, 便不可停下来。,4.adv.,(1). 也可意为“一次”的意思。 once a day.一天一次I see them once every two months. 我每两个月与他们见一次面。 (2).意为“曾经；一度；从前”。它是一个不确定的时间副词，如： a once powerful nation曾经很强盛的国家 Once known

3、, his face is never forgotten.曾经认识，他的面容让人永生难忘 Once he lived in America, but now he lives in England.他曾经生活在美国，但现在他生活在英国。,(3).乘以一; (亲属间行辈上)小一辈; a cousin once removed 堂表兄弟姊妹的孩子 Once two is two. 一二得二。 (4).用于否定句，一次也(不); 完全(不) I couldnt once understand what he meant.我完全不懂他的意思。,注意： I once went to Shanghai.

4、 我曾经去过上海。 I went to Shanghai once. 我去过上海一次。,Once的特殊用法,（1）“Once+过去分词”做后置定语，可理解为“if once”，具有条件的含义，例如 This rule once learned will never be forgotten. If once this rule is learned it will never be forgotten. A fish once taken out of the water soon dies. If once a fish is taken out of the water it will d

5、ie,(2)Once连接一个省略句（省略与主句相同的主语或it及相应的be）,Once combined,nitrogen is no longer chemically inert gas . (once nitrogen is combined，it is not chemically inert any longer.) The magnesium has to be warmed to start a rapid reaction, but once started, large quantities of heat and light energy are liberated. (b

6、ut once it is started,)镁必须予以加热才能迅速反应，一旦反应开始就会放出大量的热和光。,氮气一经化合就不再是惰性气体,Once的短语,once-forbidden.一次禁戒的 once-through.强制循环 all at once突然; 同时 at once立刻, 马上; 同时 every once in a while美偶而 for this once (=for once, just for once)就这一次; 破例一回 if once (=when once)一旦 more than once不止一次, 多次 not once一次也不 once and aga

7、in一再, 再三,once and away一劳永逸; 限此一次; 断然, 爽快 once for all一劳永逸; 永久地; 彻底地 once in a while有时, 间或, 偶而 once more再一次 once again再一次 once or twice一两次; 有时, 偶尔 once over lightly从头到尾马马虎虎地 once too often又(多了)一次,every（形容词） 与once,The Olympic games are held every four years. The Olympic games are held once four years.

8、 奥运会四年举办一次,Once与as soon as,引导的是状语从句时，主句一般将来时，从句用一般现在时表示将来 Physics is easy to learn once you understand the rules. 一旦你理解了规则，物理就不难学了. I will tell him the news as soon as he comes back. Well let you know as soon as we come to a decision. 我们一有决定，马上通知你.,once引导时间和条件状语连词 as soon as引导是时间状语连词 I will buy the

9、whole world once I get rich. 我 一 旦 有 钱 了 ， 就 要 把 整 个 世 界 买 下 来 。 I will buy the whole world as soon as I get rich. 我 发 财 的 那 一 刻 就 把 整 个 世 界 买 下 .,assureensureinsure reassure, assure, assure用来表示向某人保证某事将要发生，既可以用来确证某事，也可以表示使某人确信. assure的宾语通常是人或人称代词，所以不能直接搭用that clause。其常用结构为：assure sbof sth He assured

10、 us of his ability to solve the problem他向我们保证他有能力解决这个问题。 We booked early to assure ourselves of（getting）good seats我们及早订座以保证我们能得到好座位。 assure后还可跟抽象名词作宾语，此时与ensure同义，表示确保。 Weeks of practice assured (ensured) success in the match几个星期的训练确保了在比赛中获得成功。 Nothing can assure permanent peace没有什么能确保永久和平。 assure在英

11、国英语中作为专业术语，有 to insure assure against death投保寿险（life assurance insurance人寿保险）, ensure, ensure的意思是使某行为或某件事的结果得以保证，即确保某事发生（to make sure that sthhappens）。ensure后可以直接跟 that-clause，并可以用复合宾语。 常用结构为：ensure sthensure that clause en-sure obj（i）obj（d） To ensure the childs quick recovery，the doctor gave him an

12、 antibiotic为使这个孩子尽快恢复，医生给他打了一剂抗生素 Registration ensures delivery of mail挂号寄邮件保证会送到。 ensure也可以表示确保安全，免遭伤害。 To ensure freedom against tyranny反对暴政，维护自由 在美语中ensure常拼写为insure。, insure,为防不测向保险公司付钱投保(经济意义) My house is insured against fire我的房子保了火险。 Are you insured for all risks？你是不是给自己保了综合险？,reassure,表示安慰忧虑不安的人，使其安心，放心，恢复信心 常用结构为： reassure sb（about sth）reassure sb that clause I was worried that my work wasnt good enough，but the teacher reassured me（about it）我担心我的作业不够好，