【简析】 分析句子结构，前后两句话用逗号隔开，应该为主从句关系，由此判断后面是一个非限定性定语从句，由于关系代词前面有介词，因此只能选A项，80% of which are sold abroad修饰先行词half a million pairs of shoes, 说明其部分情况。

3. The WWF believes that our world has a future only if people learn to conserve nature and not waste energy. As a result, it started working with governments to introduce environmental education into school.

【考点】 句子中As a result表示"因此，结果"，相当于副词Therefore或Thus的含义和作用；还可以用于介词短语as a result of...中表示"由于......的结果"。

【考例】 My cousin must have made an effort to get himself into shape. ________, at the point in our game when I predicted the score to be about 9 to 1 in my favor,

it was instead 7 to 9-and Ed was leading. (2003全国卷 完形填空)

A. After all B. As a result

C. Above all D. At last

【简析】此题考查的是各短语用法比较：after all 说明让步关系，表示"毕竟，终究"；as a result说明因果关系，表示"因此，因而"；above all说明突出某方面的重要性，表示"最重要的是"；at last说明时间，表示"最后，最终"。根据句意可知选B。