2014年托福考试口语机经预测7

　　内容简介：

　　Task 4-21(131012 已考)

　　Task 4-22

　　reading 里讲一个概念 adjustable group size。是说对于种群来说有个合适种群规模。lecture里面教授举例解释这个概念。例子讲狒狒 baboon 外出觅食时一般一大堆聚在一起,可以防狮子,说明有时候数量大好。但教授又说,食物 短缺时,一大群就不好了,不如分成小群,更容易吃饱。

　　Creatures of all shapes and sizes have the ability to maintain a social structure that is efficient for its purpose. Not only does humans have this skill, even animals have shown to possess it. This skill allows the animals to regulate the group size in relation to the purpose of it. In circumstances where a large group would be necessary the animals would gather together, while in other instances where a large group would seem ineffective the pack tends to break off into smaller groups to complete their tasks.....