Question

Mary __________ the job he offered to her, but she didn’t. A

Answer 1

B

考查虚拟语气。Ought to have taken="should" have taken意为：本应该做却未做；

根据后面的but she didn’t可知这是一个与过去事实相反的虚拟语气。

应该用：情态动词+have done的形式。