Nowadays, we can find advertisements almost e  1  we go. An advertisement uses words and p  2  to attract people to buy goods or s  3 . This kind of advertisements is c  4   commercial(商业) advertisements. Newspapers, magazines, the Internet and t  5  are the most common places to find them.
The other k  6  of advertisements is public service advertisements(PSAs). The aims of PSAs are to teach us and help us lead b  7  lives. You have probably seen or heard some of them, such as “knowledge changes life.” There are also PSAs that e  8   people to support public service projects, such as Project Hope. There are even PSAs to teach us how to live healthy lives. One of these is, “When you smoke cigarettes, you are s  9  killing yourself.” You can often learn a lot by f 10  the advice they give.