1.________ caused the accident is still a complete mystery.
A.What B.That C.How D.Where
答案 A
解析 主语从句中缺少主语，而能在主语从句中既充当主语又起引导作用的只有what。
2.I just wonder ________ that makes him so excited.
A.why it does B.what he does
C.how it is D.what it is
答案 D
解析 wonder后面的宾语从句本是“what makes him so excited”，但what需要被强调，故用强调句型。
3.Water，which seems so simple and common，is ________ makes life possible.
A.what B.that
C.which D.how
答案 A
解析 考查名词性从句的连接词。句意为：看似简单平常的水是使生命出现成为可能的东西。what引导表语从句并在句中作主语。
4.I’d like to work with ________ is honest and easy to get on with.
A.who B.whoever
C.whomever D.no matter who
答案 B
解析 所填词在宾语从句中作主语。who表达的意思不对，也不符合句子结构;whomever不能在句中作主语;no matter who不能引导名词性从句。
5.When you are reading，make a note of ________ you think is of great importance.
A.which B.that
C.what D.when
答案 C
解析 宾语从句中you think是插入语，从句中缺少主语，which意思不对，故选what。
6.Mr.Smith asked the boy a question________he could go to the concert with him.
A.whether B.that
C.what D.if
答案 A
解析 考查同位语从句。if不能引导同位语从句;句中缺少疑问词“是否”，故选A项。句意为：史密斯先生问了男孩一个问题，问他是否能和他一起去音乐会。
7.A warm thought suddenly came to me ________ I might use the pocket money to buy some flowers for my mother’s birthday.
A.if B.when
C.that D.which
答案 C
解析 考查同位语从句。that引导的从句是对a warm thought的解释说明。句意为：我突然产生了一个温情的想法，在母亲生日那天我可以用零用钱给她买花。
8.There is much chance ________ Bill will recover from his injury in time for the race.
A.that B.which
C.until D.if
答案 A
解析 that引导同位语从句，具体说明chance(可能性)的内容。
9.When asked ________ they needed most，the kids said they wanted to feel important and loved.
A.what B.why
C.whom D.which
答案 A
解析 本题考查宾语从句的连接词。该连接词既引导了宾语从句，又在句中作needed的宾语，故只有what符合题意。
10.The reason ________ he didn’t come is ________ he was ill.
A.why;that B.that;why
C.why;because D.why;what
答案 A
11.With his work completed，the businessman stepped back to his seat，feeling pleased ________ he was a man of action.
A.which B.that
C.what D.whether
答案 B
解析 pleased后面缺少宾语从句，he was a man of action句意完整，故用that引导。
12.Nobody believed his reason for being absent from the class ________ he had to meet his uncle at the airport.
A.why B.that
C.where D.because
答案 B
解析 本题考查同位语从句。reason后面有for引导的短语，接着后面是that引导的同位语从句来说明reason的内容。
13.The shopkeeper did not want to sell for ________ he thought was not enough.
A.where B.how
C.what D.which
答案 C
解析 本题考查宾语从句。介词for后接宾语从句但宾语从句中缺少主语，he thought是插入语，连词what引导宾语从句且在从句中充当主语，which的意思不符合。
14.He noticed that the straight part of the dance was different in the afternoon from ________ it had been in the morning.
A.that B.where C.what D.which
答案 C
解析 介词from后是宾语从句，但从句中it had been后面少表语，所以what符合语意。
15.—Can we get everything ready by the weekend?
—It all depends on ________ we can get Mr.Green’s cooperation.
A.that B.what C.whether D.if
答案 C
解析 答语句意为：这取决于我们是否能得到Green先生的配合。介词on后跟宾语从句，从句中含有不确定因素，故用whether引导。if不能引导宾语从句。
16.________ wants to stay in a hotel has to pay their own way.
A.Anyone B.The one
C.Whoever D.Who
答案 C
解析 ________ wants to stay in a hotel为主语从句，从句中缺少主语，A、B两项可作主语，但不是连词，故排除。who只有疑问的意思，意为“谁”;whoever意为anyone who “任何……的人”，符合题意。
17.The boss refused to sell the car for ________ he thought was not satisfactory.
A.that B.which C.how D.what
答案 D
解析 可把此处的he thought作为插入语，what作宾语从句的主语。句意为：那位老板拒绝以不满意的价钱卖车。
18.It makes little difference to me ________we go or stay.
A.whether B.where C.that D.how
答案 A
解析 whether...or...或者……或者……，whether引导的从句为真正的主语，it为形式主语。
19.—The two people speak different languages and can not communicate with each other well.
—Oh，I see.That’s ________ misunderstanding occurs.
A.when B.what C.that D.why
答案 D
解析 考查表语从句。结合语境“这就是误解产生的原因”可知，此处应用why引导表语从句。
20.Before the sales start，I make a list of ________ my kids will need for the coming season.
A.why B.what C.how D.which
答案 B
解析 句意为：在大甩卖开始前，我把孩子们在下个季节里要用到的东西列了一个清单。分析句式结构可知，空格处在句中引导宾语从句且在从句中充当need的宾语，所以B项正确。which引导名词性从句时多表示疑问且要有一个明确的范围。
21.—We were surprised to hear that the reason ________ she gave for her absence was ________ her mother was ill.
—Yes.We saw her mother was at the supermarket that morning.
A.why;that B.which;that
C.that;because D.why;because
答案 B
解析 第一空可填which或that来引导定语从句，而第二空的表语从句必须用that引导。
22.________ the football match will be played depends on the weather.
A.If B.Whether
C.That D.Where
答案 B
解析 根据句意及句子结构可知该句为主语从句，故排除D项;又因语境中含有“是否”之意，故排除C项;whether引导的主语从句可置于句首，但if引导的主语从句只能用it作形式主语，而把从句放在句末，故排除A项。
23.—How did you deal with the order?
—I handed it to ________ I think is in charge of sales.
A.who B.when
C.whoever D.whomever
答案 C
解析 句中有介词to，可知空格处引导宾语从句。空格后的I think可看作插入语，句子缺少主语，用whoever，表示“任何……的人”。who没有这种意思;whomever在句中作宾语。
24.________ is known to us all is that the old worker，for ________ life was hard in the past，still works hard in his seventies.
A.As;whom B.What;whose
C.It;whose D.What;whom
答案 D
解析 考查名词性从句和定语从句的引导词。第一个空中what引导一个主语从句，并作从句的主语。第二个空代替先行词the old worker，并作介词for的宾语，用whom。
25.Can you tell me________it was________your cellphone was lost?
A.where;that B.which;that
C.that;where D.where;which
答案 A
解析 where引导宾语从句，且从句中包含强调句型。
