问题补充：
-Tom has a lot of parties recently.
- Yes, that may why he didn’t do well in the test.
A. sum up
B. add up to
C. account for
D. make sense of
答案：
A. sum up
B. add up to
(答案→)C. account for
D. make sense of
解析：考查动词短语辨析。A合计，总计；B共计达…:C 解释，说明；占据…;D理解；句意：—最后Tom参加了很多聚会。—是的，那也许可以接受为什么他考试成绩不好。根据句意说明C正确。
