Question

---Look!Mr Hu is on the other side of the street．

---It ______ be him．He has gone to Lanzhou．

1. A.
   mustn't
2. B.
   can't
3. C.
   shouldn't
4. D.
   won't

Answer 1

B
can't表示推断，意为“不可能”。而其他词都没有推断的意思，都不符合语境。