Question

But for their common interests, they_____ cooperated so smoothly in the investigation of the case.

A．could have

B．will not have

C．could not have

D．have not

Answer 1

C

試題分析：考查隱含的虛擬語(yǔ)氣：句意：要不是他們的共同興趣，他們就不會(huì)在這個(gè)投資項(xiàng)目上合作的這么順利。But for是“要不是”，是隱含的虛擬條件句，But for their common interests="if" it hadn’t been for their common interests，所以主句也是虛擬語(yǔ)氣，和過(guò)去的情況相反用would/could/should have done.選C
點(diǎn)評(píng)：有時(shí)，句子沒(méi)有直接給出假設(shè)情況的條件，而須通過(guò)上下文或其他方式來(lái)判斷。這題用了but for代替if的虛擬語(yǔ)氣，主句是1、表示與現(xiàn)在事實(shí)相反的情況，主語(yǔ)+should/would/could/might+do：　2、表示與過(guò)去事實(shí)相反的情況，主句：主語(yǔ)+should/would/could/might+have done　3、表示對(duì)將來(lái)情況的主觀推測(cè)，主句：主語(yǔ)+should/would/could/might+do