新概念英语第二册课后练习答案lesson21.doc

新概念英语第二册课后习题答案详解Lesson 21练习答案 Key to written exercises1关键句型练习答案A passing planes can be heard(1.2); The airport was built (1.2); it could not be used then(1. 3); a hundred people must have been driven away(11.4-5); this house will be knocked down by a passing plane(11.6-7); I have been offered a large sum of money(1.7)C 1 A message will be sent immediately.2 All these goods must be sold.3 I told you the parcel would be received in time.4 The letter has to be delivered by hand.5 Your letter must have been lost In the post.2难点练习答案A (sample answers)The dog drove the sheep out of the field.The police drove the crowds back.I drove my car into the garage.B1 home 2 houses 3 house 4 home3多项选择题答案1. c根据课文第3-4行Last year, however, it came into use, 只有c. came into use recently 比较接近课文的实际内容，而其他3个选择都不符课文内容。2. d根据课文第8行but I am determined to stay here, 只有d. has refused to leave his house 与课文内容相符，其他3个选择都与事实不符。3. c只有选c. can hear 才能使这个句子同前一句Passing planes can be heard night and day 的含义相同，只是语态不同。 而其他3个选择a. can heard, b. can to hear, d. can be heard 都不符合语法，在意思上都讲不通。4. d只有d. possible 才能使句子同前一句It couldnt be used then 意思最接近。a. able （能）需要人作主语，本句的主语是it 形式主语;b. allowed（允许）不符合题目的意思， c. impossible（不可能的）与句子意思相反。5. a前面句子Over a hundred people must have been driven away 中的must 表示说话人的一种主观推测。 b. Im sure(我确信) 语气比较肯定，不表示推测；c. Certain(肯定的)是形容词，缺主语和谓语，不符合语法和题目意思。； d. Of course(当然) 表示“肯定”的意思，也不够准确； 只有a. I think(我想，我认为) 表示推测，所以应该选a. 6. c只有c. are some left 才能使这个句子比较接近前一句I am one of the few people left,因为few(少数几个)同some(一些)意思比较接近, a. are none left(一个没剩)不等于the few. b. is one left(剩下一个)也不等于the few; d. are a lot left(剩下很多)与the few 意思相差悬殊. 所以选c.7. b这是一个疑问句，需要主谓倒置语序。 a. have you been offered, C. you have offered, d. they offered you 这三个选择都是陈述句语序，只有b. have you been offered 是疑问句语序，因此选b.8. b只有b. give(给)出同前面的动词offered 词意思相近， 而a. serve(服务，服侍)， c. take(拿，带)， d. make(做，制造) 这3个选择都与offered 意思不同。9. ab. number 只能修饰人，不能修饰不可数名词money, c. some不符合语法，意思不成立； d. piece 只能修饰不可数名词，但是不能修饰money.只有a. amount(很多，一大笔)表示金额，可以修饰money. a large amount of很多，一大笔,表示金额，a number of是只用于可数名词10. d只有d. am going to 才比较接近前一句I am determined to stay here.(我决定留在这里)的含义。其他3个选择中：a. am will to 不符合语法； b. want to(想要)与be determined to 的含义有些差距；c. may (可以) 词意思更不正确。11. c只有c. Perhaps 才能与前一句中的they are probably right(他们可能是对的)意思相吻合，表示“可能”，“也许”（不肯定的推测）， 而a. Of course(当然)， b. Its certain( 肯定)， d. Its sure(