拓展背景即从给出的话题中找出这个现象产生的`原因来扩展背景句。这种方法适合大多数的话题，考生要尽量在考前做练习，这样在考试就可以得心应手了。
请看下面的例子：
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?
这个题目中给出的话题是mobile phone，所以考生可以从它产生的原因来考虑，就是科技的繁荣，而科技的繁荣，手机的广泛使用是在20世纪末，这样背景句就有内容可写了。当然要通过相应的句型来写了。如
witnessed
这个背景句就可以写成：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?
