VOA慢速英语:West Africans, Free Markets and the '08 Food Crisis

conj.如果

例句：Suppose he can't come, who will do the work?
       如果他不能前来, 谁来做这项工作呢?

2.double vt.vi.是…的两倍, (使)加倍

例句：The house has doubled in value since I bought it.
      自从我买下这幢房子以来, 它的价值已增加了一倍。

类似的词语：

halve vt.把…分成两半;把…减半，对分

例句：The shares have more than halved in value since the summer high of 572p.
      股价从夏天572 便士的高价已经下跌了一半以上。

3.independence n.（国家的）独立, 自主, 自立

例句：By the time they get to that age they will value their independence.
      当他们到了那年龄时他们会珍视自己的独立性。

4.tariff n.关税, 关税表, 货物课税表

例句：There is a very high tariff on jewelry.
      宝石类的关税率很高。

5.gain vt.vi.获得, 赢得

例句：The man gained a lot in the business, but he lost the respect of his friends.
       那个人做这买卖赚了很多钱, 但他却失去了朋友们对他的尊敬。