Question

---You look tired.

---Yes. I ________ without rest until twelve o'clock.

1. A.
   am working
2. B.
   was working
3. C.
   has worked
4. D.
   had worked

Answer 1

B
本题考查时态。由句中“直到十二点为止”可以判断，这是描述与现在时间无关的过去动作，用过去进行时。