题目内容：

课文填空请根据所学课文原文填写空缺处的单词 (共20个空格；每空0.5分，满分10分)

Aspirin was invented in 1897. However, the __1.___ chemical used to make aspirin can be found in nature. Nearly 3,500 years ago, people __2.__ on leaves or drank a kind of tea made from leaves ___3.__ a special chemical to reduce body pains and __4.___.

It was in 1897 that a __5.___ chemist called Dr Felix Hoffmann produced aspirin from this chemical. The first ___6.__ of this medicine took place in 1899, when the company Hoffmann worked for began ___7.__ the medicine in powder form to physicians to use with __8.___. A year later, in 1900, aspirin was sold in shops in the form of __9.___.

However, a recent survey __10.___ in the USA shows that 80 per cent of Internet users __11.___ it mostly to search for answers to questions. The second most common use of the Internet, for 79 per cent of Internet users, is to find out information about __12.___. These statistics __13.___ that gathering information is the __14.___ use for the Internet.

Another truly wonderful __15.___ of the Internet is the way people use it to build social ___16.__. One of the greatest benefits of Internet friendships is that they are __17.___ on common interests, rather than ___18.__ or age. Young people from __19.___ backgrounds and different countries can form friendships that will last their __20.___ lives.