问题补充:
Jack doesn’t smoke now, but he for almost twenty years.
A. was smoking
B. had smoked
C. has smoked
D. smoked
答案:
A. was smoking
B. had smoked
C. has smoked
(答案→)D. smoked
解析:考查时态,由后面的时间状语for almost twenty years,可以知道是一般过去式,句子意思“杰克现在不吸烟了,但是他吸烟将近”