Making a public speech is the thing that most people don't want to do. The reason is that we are all afraid of making mistakes in front of others. The more important the speech is, the more frightened we will be. But forget it now. Public speaking is easy. It's just a simple talking, Although I'm a shy man, I've been making speeches and talking on radio and television for more than 30 years. Anybody who can talk can speak in public. Here are some of the lessons I have learned:

    Keep your speech simple. Your audience can't take all of your main ideas, and they can only remember one or two of them, not ten or twenty. So you should prepare one or two of your main ideas very well. But if you can't express what you want to say, then your speech will not be paid attention to. And if you don't have a clear idea of what you want to say, your audience won't, either.

    Organize your speech well. No matter how long or short your speech is, you have to organize your speech—how you are going to open or begin, what main points you want to make and how you're going to close or end. A strong close is usually very important and critical(关键的): the last thing you say is what your audience will most likely remember. If not, they will be confused.

    Keep your speech not long. The standard (标准的) length of a speech is usually 12 minutes. Most people can't put their minds in one thing for too long time, which will make them tired and lose their interest. If you pay no attention to your audience's reaction(反应)，the audience will get bored. Of course, your speech will fail.

    Following these suggestions above, you can make a good speech in public, and you will be an excellent speaker, I think.

杜飞同学对下列各种事物进行了估测，其中你认为正确的是（　　）

进入青春期，我们的生理在发生变化，我们的心理也发生着一系列的变化。下列变化中，我们应尽快纠正的是（    ）