蒋健棠英语广播 Episode16:师资缺乏得到解决（在线收听）

1. expand，扩展，扩大。
eg:He is thinking of expanding his business.
他正考虑扩展他的生意。

2. keep up with...根上...。
eg:They walked so fast that I could not keep up with them.
他们走得那么快,我没法跟上。

3. demand,要求，需求。 domestic demand,内需。
eg:Demand for a product usually determines supply.
一种产品的需求往往影响供应。