——　Was that the new comer who walked by? ——　＿＿＿＿＿. A. It must be thatB. It must have been

问题补充：

——Was that the new comer who walked by?

——＿＿＿＿＿.

A. It must be that

B. It must have been

C. He must be

D. This must have been

答案：

A. It must be that

(答案→)B. It must have been

C. He must be

D. This must have been

解析：表示对过去情况的猜测，用“情态动词＋have done”；而it代替上文所指的new comer。