英语单项知识的讲解与练习(47).doc

英语单项知识的讲解与练习（47）231、if的用法 （1）、有些时间、地点、条件、原因、让步、比较和方式状语从句中，如果谓语包含be，主语又和主句的一致，或主语是it 时，常可以省略从句中的主语和谓语的一部分(特别是be)，省略的条件状语从句有以下几种形式： 1)、if + 形容词，如：if necessary = if it is necessary；2)、if + 副词，如：if not sooner；3)、if/ unless + 过去分词，如：unless invited。省略的时间状语从句常以when/ while/ till/ until 等引导。（2）、whether与or not连成一个词组、whether在不定式之前、whether引导的从句放在句首、whether引导主语从句、表语从句、让步状语从句（意为“不管”），以及在介词后，只能用whether，不能用 if。（3）、if so/ if not 用来代替完整的从句。（4）、If it were not for/ If it had not been for如果没有,要不是(虚拟语气)这一结构表示一个特定的情况改变了一切,如省if,只能把were提前,not放在it后,不可把werent放在句首。如: If it were not for his wifes money ( = Were it not for./ = without.), hed never be a doctor如果不是他的妻子有钱,他永远不会成为一个医生。（5）、 如宾语从句中出现否定式,一般用if,不用whether,如: I dont care if it doesnt rain下不下雨与我关系不大。 (6)、条件句中有were, had 或should 等助动词时，should 可省，从句用倒装形式。如：Were I in your position, I would go.练习：I will go _ I die for it. A. when B. if C. while D. as _ the sun were to rise in the west, I would not break my word. A. If B. Unless C. When D. Though _ he had not hurt his leg, John would have won the race. A. If B. Since C. Though D. WhenCould I use your English dictionary?Im sorry, but it isnt here. Id get it for you _ I can remember who last borrowed it. A. except that B. now that C. if only D. even though232、have increased to 3000. （1）、increase by + 倍数或百分数,表示增加了倍或百分之，如：The area has an increase in population of 20 percent = The population of the area has increased by 20 percent = The area has a population increase of 20 percent.增加了20%； （2）、increase to + 具体的增长后的数字,表示增加到了，如：The number of students has increased to 3000.练习：The number of the employees has grown from 1000 to 1200. That means it has risen _ 20 percent. Aby Bat Cto Dwith One of the consequences of our planets being warming up is a(n) _ in the numbers of natural disasters. A. result B. account C. reason D. increase If their marketing plans succeed, they _ their sales by 20 percent. A. will increase B. have been increasing C. have increased D. would be increasingA clean environment can help the city bid for the Olympics, which in return will _ its economic development. A. add B. increase C. promote D. plusThe first use of atomic weapons was in 1945, and their power _ increased enormously ever since. A. is B. was C. has been D. had been233、take/ show/ have an interest in （1）、interest 前有形容词修饰时要带上a/ an 。动词interest/ surprise/ frighten/ satisfy/ excite/ worry等有“使人感到”的用法，这些词成为分词后具有共同的用法，即现在分词均可表示“令人感到的”，而过去分词则表示“对感到的”； （2）、be interested in doing something 指将要（或可能）发生的事，对做某事的想法感兴趣。 （3）、be interested to do something指已经发生的事，意思为对所了解的事或经历的事感兴趣。 （4）、He was deeply interested that I had bought so rare a book他对我买了一本珍贵的书深感兴趣；练习：What _ me most is that such a pretty girl _ interest in raising pigs. A. interests; takes so much B. takes interest to; has such great C. interest; shows so much D. interesting to; feels so much He is _ in the _ film. A. interesting; interesting B. interested; interested C. interested; interesting D. interested; interests I was interested _ in the paper that scientists had found out how to talk to whales. A. to read B. in reading C. reading D. with reading The old man watched the young boys playing _ basketball with _ great interest. A. a; a B. the; the C. /; / D. /; a He is very popular among his students as he always tries to make them in his lectures. A. interested B. interesting C. interest D. to interest234、introduce somebody to somebody （1）、introduce somebody/ something to后面既可以接上人也可以接上物，意思为“向某人介绍某事物或使某人认识某事物”。如： Allow me to introduce my teacher to you. （2）、o把某事物传入或引进某地方,into后通常跟地点作介词宾语。如：The plant was introduced into China last year. （3）、make an introduction of corn into China把玉米引入中国；练习：Can you _ any proof that you werent near the bank at the time of the robbery? A. have B. introduce C. produce D. gain They wanted to have _ of the new product. A. introduction B. the instruction C. the introductions D. the introduction I hope that they will soon _ new techniques to reduce the pollution. A. introduce to B. introduction C. introduce D. introduction to The factory is _ new techniques from abroad this year.A. bringing B. borrowing C. introducing D. buying Let me introduce myself. Im Albert. _. A. What a pleasure B. Its a pleasure C. Pleased to meet you D. Im very pleased It is worth considering what makes “convenience” foods so popular, and _ better ones of your own. A. introduces B. to introduce C. introducing D. introduced235、join somebody in (doing) something（1）、join 指参加某一组织，成为其中的一个成员或参加到某些人中去。如：He joined the League last term. （2）、join in 指参加一些短暂的活动，如游戏、比赛、讨论等。如：Our teacher will come to join in our discussion. （3）、take part in 指参加群众性的活动、会议等，着重强调的是以主人翁的态度参加进去，如革命、斗争等。如： We often take part in physical labour. （4）、join in指“参加某项活动”时,和take part in有时是通用的。前者侧重娱乐、欣赏,后者侧重身体力行,参加在其中。但“参加考试”不可说：join in或take part in，而须说： sit for 或take。如： sit for/ take the making-up exam 参加补考； （5）、attend 指与别人一道出席会议、参加典礼、婚礼等，不一定起应有的作用，着重指动作。如：She is sure to attend the wedding. 练习：Were going to have a sports meeting. How many of you will _?A. join it B. join in C. take part in D. take part In the first games for the disabled in 1948 just two teams of injured soldiers _. A. took part in B. joined in C. took part D. attendedWill you join us in the game? Thank you, _. A. but why not B. but Id rather not C. and I wont D. and Ill joinWill you _ us _ her 15th birthday? A. join;