—Why wasn't John hired for the job?—I don't know but he .A. wasB. had beenC. should haveD

问题补充：

—Why wasn John hired for the job?

—I don know, but he .

A. was

B. had been

C. should have

D. should have been

答案：

A. was

B. had been

C. should have

(答案→)D. should have been

解析：D 考察情态动词和省略。句义：—为什么John没有被录用？—不知道，他本该被录用的。Should have done本该做某事，实际上却没有做；故D正确。