Question

—Did you notice John was not at work today?
—No.If _______ working,I would have noticed it.

A．I’d	B．I was
C．I’d been	D．I were?

Answer 1

C?

从“Did you notice” 可知下面的回答是针对过去情况的假设，用过去完成时，即I’d been相当于I had been。