Question

---Tom says he is too tired to go on.
---He can’t be.He ______for an hour.

1. A.
   just worked
2. B.
   has only been working
3. C.
   has just worked
4. D.
   had only been working

Answer 1

B
考查动词的时态。从本题的语境中可以看出他不可能累的原因是：他从开始工作到现在仅仅才工作了一个小时，因此应该用现在完成进行时。