Nearly 3,500 years ago,people chewed on leaves or drank a kind of tea made from leaves_______a special chemical to reduce body pains and fever.
Fleming immediately realized that the mould might have an________in treating illnesses caused by bacteria.
Not only has aspirin proved________for reducing fever and helping stop pain,but there are also other things that aspirin can help with.
Some people claim that surfing the Internet is a waste of time.They make the________that children spend too much time chatting and playing games instead of focusing on their school work.
Subject directories are built by humans.Someone has________pages and links and selected all those that are in the directory.
Young people from________backgrounds and different countries can form friendships that will last their entire lives.
When people need information,from the news and weather forecasts to travel packages and academic research,the Internet is now the first source they________.
This study shows that people who spend too much time on the Internet tend to________from the people and the world round them.