Question

Mary’s score on the test is the highest in her class; she _________ have studied very hard．

[　　]

A．

may

B．

should

C．

must

D．

ought to

Answer 1

答案：C
解析：

玛丽的考试分数在班内最高，由此推断，她一定是努力学习了，用must have studied。