昨天本来是想说说那个人奔五张的Dave大叔的事，没成想误入歧途、做白日梦了！
Dave属杂牌军序列，干技工三十多年养家糊口，孩子现在都独立了，才进入大学读副学位，希望实现从技工变成工程师的多年梦想。这是他的第一学期，开初选了四门课，最后只选择这门基础数学和工程静力学。他的基础的确很差，虽然一直在稳步上升，还时常犯低级错误。就在星期一的课堂上，他还在问：你怎么从三分之一除二分之一直接得到的三分之二？就他这个数学基础，工程静力学简直就是天书。不过，他的努力是不容置疑的：为了星期四交工程静力学作业，他缺席了星期二的数学课。
Dave星期五中午找我时，我正在和我的博士生讨论如何根据审稿人的意见，修改他的第四篇杂志文章。（这个学生来自伊拉克，很聪明、有主见、也非常有趣，是我指导过的最好的博士生。）我告诉他12.30再来。
Dave问的是三角和三角函数里角的基本转化。他的课本（我的新书）上贴着五颜六色的纸条。我跟着他的路标、一页一页给他解疑。进入三角函数后，路标消失了，像进入了未开垦的处女地。
我笑着问他：You
haven’t read this chapter, have you? 他不会意思地说：I
read some sections but didn’t put much effort, to be honest. I spent almost 90
hours in last seven days on my statics assignment, even missed the math class
on Tuesday.
之后，他翻开笔记本，让我看他不会做、做不对的题。真是百闻不如一见！怪不得那仨小姑奶奶曾经不止一次地赞叹Dave的笔记整洁工整！
我冲口而出：No
wonder those girls praised your notes so much. Dave, you should consider
becoming a high-school math teacher, rather than an engineer.
Dave回答: My math isn’t good, actually is poor. I
would consider being a math teacher in high schools if my math could be as good
as 10% of yours.
我摇着头说：It’s
not about math knowledge and skills. It’s about the personal characters and communication
styles. My teaching style is only suitable to adult students or university environment.
I am more like a mentor. I lack patience and cannot tolerate repeating the same
thing again and again. However, these are the essentials for high school
teachers. You have these characters and your notebook is a reflection of such.
Young kids would love your neat and clear handwritings on the board.
Dave也摇头回道：Young
kids may not write notes by hand anymore. Look the two girls in the class. They
just type anything important straightway into their tablet or laptop. I’m just
too old to adapt the high-tech.
我调侃：We are dinosaurs, aren’t
we?
Dave笑着说：Oh
yeah, we are dinosaurs alive!
