问题
选择题
— The woman biologist stayed in Africa studying wild animals for 13 years before she returned.
— Oh, dear ! She ______ a lot of difficulties !
A．may go through
B．might go through
C．ought to have gone through
D．must have gone through
答案
D
此句是对已经发生的事情的肯定的猜测，故排除A、B。根据句意，排除C。故答案为D。