Question

Mr White ________ at 8∶30 for the meeting, but he didn't show up．

1. A.
   should have arrived
2. B.
   should arrive
3. C.
   should have had arrived
4. D.
   should be arriving

Answer 1

A
全句意為“懷特先生8∶30(原本)應該到會的，但他沒露面”。全句談的是過去應做的事但沒有做，故應使用should have done結構，表原本該做而沒做某事。故答案為A。
一定要掌握should have done/ought to have done表示“應該做的事而未做”。同時，也要注意情態動詞的同類結構的不同用法。如：must have done表示對過去肯定的推測，can't have done是表示“對過去否定的推測”。