haha, i did once in elementary school, those little folks were so naughty.
let me find a pic later.

btw, dont use powerpoint to help them to understand. try to find some interesting pictures or toys

[此贴子已经被作者于2004-11-17 10:52:31编辑过]

biology的就讲21世纪是生物世纪，发展如何快，分子技术和基因发展的前景，泛泛点就行，呵呵~~