Difference

　　"I can always tell a graduate class from an undergraduate class," observed the instructor in one of my graduate engineering courses at California State University in Los Angeles.

　　"When I say, 'Good afternoon,' the undergraduates respond, 'Good afternoon." But the graduate students just write it down."

　　“研究生班和本科生很容易就能区别开来，”在洛杉矶加利福利亚州立大学给我们研究生上工程学课的.老师如此说。

　　“我说‘下午好’，本科生们回答说‘下午好’。研究生们则把我说的话记在笔记本上。”