Among the many ways in which people communicate through speech, public speaking has probab

ly received more study and attracted more attention than any other. Politicians campaigning for public office, salespeople presenting products, and preachers delivering sermons all depend upon this form. of public communication. Even people who do not make speaking a part of their daily work are often asked to make public speeches: students at graduation, for instance, or members of churches, clubs, or other organizations. Nearly everyone speaks in public at some time or other, and those who perform. the task well often become leaders.

There are many reasons for speaking in public. A public speaker may hope to teach an audience about new ideas, for example, or provide information-about some topic. Creating a good feeling or entertaining an audience may be another purpose. Public speakers, however, most often seek to persuade an audience to adopt new opinions, to take certain actions, or to see the world in a new way.

Public speakers usually know well in advance when they are scheduled to make an address. Consequently, they are able to prepare their message before they deliver it. Sometimes, though, speakers must deliver the message unprepared, or off the cuff, such as when they are asked to offer a toast at a wedding reception or to participate in a televised debate or interview.

When they do not have to speak unprepared, most speakers write their own speeches. Politicians and business executives sometimes employ professional writers who prepare their speeches for them. These professional writers may work alone or in small teams. Although the speaker may have some input into the contents of the speech, the writers sometimes have a great influence over the opinions expressed by their employers. Regardless of how a speech is prepared, the person who delivers it is given credit for its effect upon its hearers.

Public speaking is well known to the average people because______.

A．most of them have been trained as public speakers

B．such activities are prevalent in the society

C．most of them have to do it when they study at college

D．the passage does not mention the reason