---Do you still smoke heavily?No. In fact it is two years since I .A. have stopped sm

问题补充：

---Do you still smoke heavily?

--- No. In fact, it is two years since I .

A. have stopped smoking B. smoked

D. began to smoke D. started to smoke

答案：

解析：考查since结构。it is two years since I 。ince后面跟延续性动词，表示在动词动作结束后已经两年了。即我不吸烟已经两年了，吸烟这一动作发生在过去，所以用一般过去时态。选B。