"I can always tell a graduate class from an undergraduate class," said an instructor at a university graduate engineering course. "When I say 'Good afternoon,' the undergraduates respond 'Good afternoon.' But the graduate students just write it down."

一个教师在研究生工程学课堂上说：我一眼就能看出来哪些是本科生，哪些是研究生。 我说下午好的时候，本科生回答下午好，而研究生则把这句话记在本子上。