拓展背景即從給出的話題中找出這個現象產生的`原因來擴展背景句。這種方法適合大多數的話題，考生要儘量在考前做練習，這樣在考試就可以得心應手了。
請看下面的例子：
There are social, medical and technical problems associated with the use of mobile phones. What forms do they take? Do you agree that the problems outweigh the benefits of mobile phones?
這個題目中給出的話題是mobile phone，所以考生可以從它產生的原因來考慮，就是科技的繁榮，而科技的繁榮，手機的廣泛使用是在20世紀末，這樣背景句就有內容可寫了。當然要通過相應的句型來寫了。如
witnessed
這個背景句就可以寫成：The late 20th century witnessed the boom of science and technology, which gave rise to a series of technological innovations, including the mobile phone.
再看一例：
Nowadays, some universities offer students skills that assist them to find employment, but some people believe that the main function of a university should be to provide students with access to knowledge for its sake. What is your opinion?
