26. We agree to accept _________ they thought was the best tourist guide.
A. whatever
B. whomever
C. whichever
D. whoever
27. Although many people view conflict as bad, conflict is sometimes useful _________ it forces people to test the relative merits of their attitudes and behaviors.
A. by which
B. so that
C. in that
D. provided that
28.A beam of light will not bend round corners unless _________ to do so with the help of a reflecting device.
A. made
B. being made
C. having made
D. to be made
29.A knock at the door again! It was the third time someone _________ me that evening.
A.has interrupted
B. had interrupted
C.to have interrupted
D. would have interrupted
30. The government agrees to install services _________ by residents over a ten-year period.
A. which are to be paid for
B. for which to be paid
C. which to be paid for
D. to be paid for which
試題及答案解析：
26. Dwhoever引導(dǎo)名詞性從句，并在從句中做主語，用來指人。they thought 是插入成分。
27. Cin that“是因為”，引導(dǎo)原因狀語從句，符合句意。by which表示手段;so that引導(dǎo)目的狀語從句;provided that引導(dǎo)條件狀語從句。
28.Amade to do so是it is made to do so 的省略形式。unless是連詞，應(yīng)連接句子，所以除A以外的其他幾個選項都是錯誤的。
29.B此處用過去完成時，是因為本句意指“到那次敲門，已經(jīng)是第三次有人打攪我了”。句中用詞was和that evening都說明指過去發(fā)生的事，到過去某一時刻為止已出現(xiàn)的情況用過去完成時。
30.Awhich在句中是關(guān)系代詞，要引導(dǎo)一個句子，而B、C、D三個選項中都沒有謂語，因此不是句子。本句意為：“政府同意提供服務(wù)設(shè)施，經(jīng)費由居民在十年期間償還�！�
