VOA慢速英语:Turning Cigarette Butts to Batteries

短语讲解：

1. He began wondering if something useful could be made from them.

be made from 由…所做成的（用于原材料不易看出的场合）
例句：The ring will likely be made from a nugget of welsh gold.
戒指很可能是由一块珍贵的威尔士金打造而成。

2. The filter is the part of the cigarette that smokers put into their mouths.

put into 用…表达; 投入
例句：If you go on like this you will be put into prison. 
你这样下去会进监狱的。

3. In other words, carbon can easily carry an electrical current.

in other words 换句话说; 就是说
例句：In other words, it must be visible to manipulate it. 
换句话说，必须是可见的，人们才能操作。 

4. Super-capacitors are good at storing energy.

be good at 精通; 熟谙
例句：Why must you be good at a foreign language? 
为什么你必须学好一种外语？