A、  B、  C、  A询问解释者的过去时who疑问句→“不知道”类型回答

Wasn’ t the side table more useful in that corner?
(A) No, it’ s on the sofa.
(B) Yes, let’ s move it back.
(C) Turn right at the corner.

Who explained this incident to you?
(A)  I don’t really remember.
(B)  Mr. Novak is involved.
(C)  There was a big accident on my way here.