I told Sally how to get there,but perhaps I ( ) for her.A.must have written it outB,had to write it outC.ought to write it outD.should have wriiten it out.为什么?

问题描述:

I told Sally how to get there,but perhaps I ( ) for her.
A.must have written it out
B,had to write it out
C.ought to write it out
D.should have wriiten it out.
为什么?