Question

---Was it the new school headmaster who walked by ?
--- _____.

A．It must be that

B．It must have been

C．He must be

D．This must have been

Answer 1

B

考查问题回答，问句是it为主语，回答也是it为主语，而且是对过去情况的推测，选B，句意是：--刚刚走过的是校长吗？--一定是。It must have been ="It" must have been the new school headmaster。