问题补充：
–Look at that girl! Is it Susan?
--No, it be her. She has gone back to her hometown.
A. mustn’t
B. can’t
C. needn’t
D. wouldn’t
答案：
A. mustn’t
(答案→)B. can’t
C. needn’t
D. wouldn’t
解析：根据后文的内容：. She has gone back to her hometown.，可知她不肯能是上文中看见的人，故选B
