听力原文：M: Hi, Susan, where were you at lunch time？ I was saving a seat for you in a cafeteria.
W: Oh, sorry m miss you. But my search for knowledge was greater than my pains of hunger.
M: I never had that problem, so where were you？
W: My political science class ran over time.
M: That's been happening quite a bit lately, hasn't it？
W: I guess so. Actually, what happens is that a bunch hung around for awhile after class to talk with our professor and asking questions.
M: Oh, really! Who is this twentieth century Socrates on earth？
W: Professor Hawl, have you heard of him？
M: Mm, he does have a good reputation in the political science department.
W: And well deserved one. The same student who falls asleep in discussion group in seminars fights front row seat in his lectures.
M: Oh, no. I hope this is in catching.
W: You can joke. But it's great to have a professor who is not only interesting, but prepared to give up time for students.
M: I know, they are real breed. Maybe I should sit in on his class sometime. Do you think he'll care？
W: Not at all. Lots of students bring their friends. He said he feel flattered.
M: I'll make a good student of you yet.
(20)

A. Giving a lecture.
B. Discussing political science.
C. Working on a science problem.
D. Reading twentieth-century literature.