Question

--- He worked out such different questions at a very young age.
--- Oh, he ______ a very smart student then.

A．could have been	B．should have been
C．might have been	D．must have been

Answer 1

D

試題分析：句意：--在這么小的年齡他就能提出不同的問題。--哦，那他當(dāng)時(shí)一定是非常聰明的。could have done過去本可以做某事而未做成； should have done 指過去應(yīng)該做某事而實(shí)際未做；might have done 表示過去可能做某事；must have done表示過去一定能做某事。根據(jù)then可知這是指at a very young age，所以表示動(dòng)作已經(jīng)過去了，根據(jù)第一句可知這里推測(cè)的可能性很大，故選D。
點(diǎn)評(píng)：本題難度適中。情態(tài)動(dòng)詞是高中階段的重難點(diǎn)之一，需要考生熟記它們的用法，在各類考試中經(jīng)常出現(xiàn)，情態(tài)動(dòng)詞的完成式主要用于表示對(duì)過去情況進(jìn)行推測(cè)或責(zé)備也是高考�？嫉膬�(nèi)容。
即學(xué)即練：I didn’t see her in the meeting-room this morning. She ____ at the meeting.
A. mustn’t have spoken    B. shouldn’t have spoken
C. needn’t have spoken    D. couldn’t have spoken
解析：D。本句表達(dá)的是過去已發(fā)生情況否定的推測(cè)判斷，應(yīng)該用couldn’t have done.