问题
选择题
．The highest award was given to Anna, who _____ so hard on the project for years, and at last her efforts paid off.
A．has worked
B．worked
C．was working
D．had been working
答案
答案：D
考查时态，句意;最高奖项被授予安娜，她从事这个项目多年，至少努力没白费，关键的句子：her efforts paid off.用过去时，而一直努力是发生在pay off，之前，用过去完成进行时。选D。