The dean of Engineering had once walked into a class, and said "Good Morning".
The whole class chorused "Good Morning".
"Hi, you are freshmen1, aren't you?" he asked.
One student bolder than the others asked him how he knew.
"Well," he said. "When I say 'Good Morning' to a class, if they are freshmen they say 'Good Morning' too. If they are sophomores2, they quietly fold their papers away, and look at me. A class of juniors will look at me over the top of their papers, and then get back to them. A class of seniors will ignore my greeting, and keep reading the papers. When I say 'Good Morning' to a class of graduate students, they write it down."
一天，工程系的主任走进一间教室说：“早上好。”
全班同学异口同声地回答：“早上好。”
“你们是大一新生吧？”主任问道。
班级里一个胆子比较大的同学问主任是如何知道的。
“嗯，”主任说，“当我说‘早上好’的时候，假如是大一的新生，他们也一定会说‘早上好’的。假如他们是大二的学生，他们会轻轻地合上课本，然后集体看着我。大三的学生则会抱着书本，抬起头看我一眼，然后又继续读书。大四的学生则根本无视我的存在，一直看着书。至于研究生班的学生，我向他们‘问早上’好，他们就会把这句话写在笔记本上。”
