3.
W：I'd like to book four tickets to Shanghai on November 28th.
M: Would you want one-way or round-trip?
W: Round-trip. We will return on December 10th, oh, no, sorry, 12th.
M: Yes, four tickets on November 28th to Shanghai and returning on December 12th.
解析：
答案为C，根据We will return on December 10th, oh, no, sorry, 12th，我们会在12月10日，噢，不对，是12日回来，得知正确答案为C，在12月12日回来。

4.
M: Jane, Professor Keller asked about you today and how you were coming along with the project on pollution. By the way, I handed mine in the day before yesterday.
W: Whoops. I was supposed to give it to her yesterday.
解析：
答案为B，根据I was supposed to give it to her yesterday.我应该昨天交给她的，可知正确答案为B，她应该昨天上交方案。