A. have solvedB. have been solvingC. have to solveD. have to be solved 正确答案：D
答案讲解：分析句子结构，主语such problems和谓语solve之间是被动关系，所以答案应选D。“主语+ have to + be +V.p.p.”的意思是“不得不被??”。句子的意思是：“这样的问题不得不尽快解决。”
6 Her application for the position ____________ by the boss. A. was refusedB. was refusingC. refusedD. is refusing 正确答案：A 答案讲解：分析句子结构，主语her application for the position和谓语refuse之间是被动关系，所以答案应选A。句子的意思是：“她申请那个职位被老板拒绝了。”
7 The event ____________ at the time last year. A. happensB. happenedC. is happenedD. was happened 正确答案：B
答案讲解：动词happen是不及物动词，没有被动语态；时间状语at the time last year表明这件事发生在过去，应该用一般过去时，所以答案为B。句子的意思是：“这件事发生在去年的这个时候。”
8 Much ____________ in the past few years. A. has done B. did
C. has been done D. was done 正确答案：C 答案讲解：主语much和动词do之间是被动关系，时间状语in the past few years是现在完成时的一个标志，所以正确答案是C。句子的意思是：“在过去的几年中完成了很多事情。”
9 Because of the rainy day, the match ____________ A. has been putting off B. has put off C. put off
D. has been put off 正确答案：D
答案讲解：主语the match和谓语put off之间是被动关系，应用被动语态，所以答案为D。句子的意思是：“由于下雨，比赛被推迟了。”
10 Working hours in the United States ____________over the past 20 years. A. have increased
B. increased
C. were increasing D. have been increased 正确答案：A
答案讲解：increase在句中表示一种状态而不是动作，所以不能用被动语态；根据时间状语over the past 20 years，可知本句应用现在完成时，表示过去发生的事情对现在的影响，所以答案为A。句子的意思是：“在美国过去的20年中，工作时间增加了。”
11 Since computers were invented, it ____________ that they are indispensable for scientific research. A. thought
B. has been thought C. is thinking D. had thought 正确答案：B
答案讲解：it在句中作形式主语，句子真正的主语是that引导的从句，而且it和think是被动关系，应用被动语态，所以应选B。句子的意思是：“自从计算机发明以来，人们就认为它们对科学研究而言是必不可少的。”
12 He was told that after he graduated he ____________ by a company. A. would be employed B. would get employed C. would be employing D. would employ 正确答案：A
答案讲解：主语he和谓语employ之间是被动关系，应用被动语态，而get employed是比较口语化的一种被动语态，这种结构中很少用by短语，所以答案为A。句子的意思是：“他被告知毕业后会被一家公司聘用。”
13 The steps of progress in society ____________ of as having happened in a short time. A. must not think
B. must not be thought C. must think D. thought 正确答案：B
答案讲解：主语the steps of progress in society和谓语think of之间是被动关系，应用被动语态，所以应选B。句子的意思是“不应该认为社会进步的步伐会在短时间内发生。”
14 His wife told him that the kitchen ____________ cleaned by the sweeper. A. was being
B. was getting C. has been D. got
正确答案：A
答案讲解：主语the kitchen和谓语clean之间是被动关系，应该用被动语态。get +V.p.p.是比较口语化的一种被动语态，这种结构中很少用by短语，故可以排除B和D。主句是一般过去时，从句也应用过去时态，故又可以排除C。所以，正确答案为A，这是过去进行时的被动语态结构。句子的意思是：“他的妻子告诉他清洁工正在打扫厨房。”
15 Owing to the snowstorm, the trip to the mountain ____________. A. has been canceling B. has canceled C. canceled
D. has been canceled 正确答案：D
答案讲解：the trip to the mountain和cancel 之间是动宾关系，所以这里应该用被动语态，用be+V.p.p.的形式，这里符合要求的只有D，因此正确答案应该是D。
Unit 5 不定式
Ⅰ. Choose the best answer to complete each of the following sentences.
1 This company was the first____________portable radios as well as cassette tape recorders in the world.
A. producingB. to produceC. having producedD. produced 正确答案：B
解析：本句需要动词不定式来做后置定语，修饰the first, 所以应选B。整句话的意思是：这家公司是世界上首家生产便携式收音机和盒式磁带录音机的公司。
2 The purpose of new technology is to make life easier,____________it more difficult. A. not makingB. not makeC. not to makeD. nor to make 正确答案：C
解析：本句需要动词不定式来做与is to make life easier并列的表语，所以应选C。整句话的意思是：新技术的目的是让生活更轻松，而不是更困难。
3 Helen had to shout____________above the sound of the music.
A. making herself hearB. to make herself hear C. making herself heardD. to make herself heard 正确答案：D
解析：本句需要动词不定式来做动词shout的目的状语，所以应在B和D之间选择。而“让自己被别人听到”应该用heard，而不是hear，所以应该选D。整句话的意思是：海伦不得不大声喊，以使别人能在音乐声中听到她的声音。
4 I don't know whether you happen____________, but I am going to study in the U.S.A this September.
A. to be heardB. to be hearingC. to hearD. to have heard 正确答案：D
解析：根据句意，这里应该用动词不定式的完成时来表示“已经听说”，所以应该选D。整句话的意思是：不知道你是不是已经听说了，反正我今年9月就要到美国留学了。
5 The news reporters hurried to the airport, only____________the film stars had left. A. to tellB. to be toldC. telling D. told 正确答案：B
解析：本句中的only to do sth.是固定短语，常在句中做结果状语，表示很令人遗憾、失望或伤心的结果，所以应从A和B中选择。根据句意，the news reporter应是动词tell的宾语，所以应该用动词不定式的被动语态，故应该选B。整句话的意思是：那位记者匆匆赶到机场，却被告知那些影星已经走了。
6 You were silly not ____________your car.
A. to lockB. to have lockedC. lockingD. having locked 正确答案：B
解析：本句需要动词不定式来做原因状语，并根据句意判断，应该用不定式的完成时，所以应选B。整句话的意思是：你没有锁车，真傻。
7 The teacher asked us ____________ so much noise. A .don't makeB. not makeC. not makingD. not to make 正确答案：D 解析：本句需要动词不定式来做ask的直接宾语，并根据句意判断，应该用不定式的否定式，所以应选D。整句话的意思是：老师让我们不要这么吵。
8 An army spokesman stressed that all the soldiers had been ordered____________clear warnings before firing any shots.
A. to issueB. being issuedC. to have issuedD. to be issued 正确答案：A
解析：本句需要动词不定式来做order的宾语，并根据句意判断，不需要用不定式的被动式或完成式，所以应选A。整句话的意思是：军方发言人强调，已经命令所有的士兵在开枪之前都必须发出明确的示警信号。
9 I'd rather have a room of my own, however small it is, than____________a room with someone else.
A. to shareB. to have sharedC. shareD. sharing 正确答案：C
解析：本句用的是would rather do sth. than do sth.句型，than后面的动词不定式一般省去不定式符号to，所以应选C。整句话的意思是：我宁愿要一间属于自己的屋子，多小都行，也不愿和别人同住一个房间。
10 The bank is reported in the local newspaper____________ in broad daylight yesterday. A. robbedB. to have been robbedC. being robbedD. having been robbed 正确答案：B
解析：本句需要动词不定式来做主语the bank的补足语，并根据句意判断，应该用不定式的完成被动式，所以应选B。整句话的意思是：据报道，那家银行昨天在光天化日之下遭到了抢劫。
11 A number of paintings in the castle are believed____________in a fire.
A. being destroyed B. having been destroyedC. to be destroyedD. to have been destroyed 正确答案：D
解析：本句需要动词不定式来做主语a number of paintings的补足语，并根据句意判断，应该用不定式的完成被动式，所以应选D。整句话的意思是：据称，古堡中的一批油画已经在一场大火中被烧毁。
12 The meeting ____________next week is sure to be a great success. A. to take place B. to be taken placeC. to have taken placeD. being taken place 正确答案：A
解析：本句需要动词不定式来做主语the meeting的后置定语，并根据句意判断，不需要用不定式的完成式或被动式，所以应选A。整句话的意思是：下周要开的会一定会取得圆满成功。
13 As a result of my laziness, I failed____________my work in time. A. and finishedB. to finishC. and finishingD. to finished 正确答案：B
解析：本句需要动词不定式来做谓语动词fail的宾语，所以应选B。整句话的意思是：因为我的懒惰，我没能按时完成我的工作。
14 I am sorry____________ written you a letter at the time. A. to have notB. to not haveC. not to haveD. not having 正确答案：C
解析：本句需要动词不定式来做原因状语，表示过去没有做到的事情，应该用不定式的否定式，所以应选C。整句话的意思是：我很抱歉当时没有写信给你。