题目内容：

They urged that the library___ open during the vacation.
a、must be
kept
b、 is kept
c、 would be kept
d、 be kept
我选择D选项,D选项为什么不对呢?老师请答疑,谢谢.
We ____ on this project for
four hours. Let’s have a rest.
选项:
a、are working
b、 have been working
c、 worked
d、 had worked
我选择B选项,我不知道为什么错了.老师请答疑,谢谢!
——Are you all right? —— ___
选项:
a、You’re welcome
b、That’s OK
c、I think so
d、Take it
easy
这题我选了B,.不知道哪个才是正确的?考试评分这几个都错了!