重点讲解：
1. roam round 漫步；漫游；游荡；闲逛；
There were gangs of kids on motorbikes roaming around.
过去有成群结队的年轻人骑着摩托车四处游荡k#%xCJP#@bCC。
2. extrapolate from 推断；推知；
Extrapolating from his American findings, he reckons about 80% of these deaths might be attributed to smoking.
根据他在美国的调查结果推断，他估计这些人中约有80％可能死于吸烟2@foLxs_s(Hrr。
3. part of 一些；部分；
The survey formed part of a larger programme of research.
这个调查是研究计划的一部分[aGbvq=#@EyMmK6Z)7。
4. look at 检查，察看；
The examples we will look at have quite different emphases.
我们将要观察的例子所强调的重点很不相同5u0CW3%LJb_q24*。