Question

【题目】By the time I got to the airport，the plane ________ .

A. have taken off B. had taken off

C. is taken off D. is taking off

Answer 1

【答案】B

【解析】

句意：等我到机场的时候，飞机已经起飞了。have taken off已经起飞了，是现在完成时态；had taken off过去完成时态；is taken off被起飞了，是一般现在时的被动语态；is taking off将要起飞，现在进行时表示将来。句中by the time引导的是状语从句，从句用一般过去时态，主句用过去完成时态，故选B。