Question

I ________ yesterday but I was too busy.

1. A.
   came
2. B.
   have come
3. C.
   should come
4. D.
   should have come

Answer 1

D
考查固定句型。should have done sth表示“本应该做某事 (但实际上未做) ”，由句意“我本应该昨天来但我昨天太忙了。”可知D项正确。