【正确答案】 B

【答案解析】[听力原文] 21-25 Listen to part of a lecture in speech class. Today we're going to practice evaluating the main tool used when addressing groups--the voice. There are three main elements that combine to create either a positive or negative experience for listeners. They can result in a voice that is pleasing to listen to and can be used effectively. Or they can create a voice that doesn't hold attention, or even worse, causes an adverse reaction. The three elements are volume, pitch, and pace. When evaluating volume keep in mind that a good speaker will adjust to the size of both the room and the audience. Of course, with an amplifying device like a microphone, the speaker can use a natural tone. But speakers should not be dependent on microphones--a good speaker can speak loudly without shouting. The second element, pitch, is related to the highness or lowness of the sounds. High pitches are, for most people, more difficult to listen to, so in general speakers should use the lower registers of their voice. During a presentation, it's important to vary pitch to some extent in order to maintain interest. The third element, pace, that is how fast or slow words and sounds are articulated, should also be varied. A slower pace can be used to emphasize important points. Note that the time spent not speaking can be meaningful, too. Pauses ought to be used to signal transitions or create anticipation. Because a pause gives the listener time to think about what was just said--or even to predict what might come next--it can be very effective when moving from one topic to another. What I'd like you to do now is watch and listen to a videotape and use the forms I gave you to rate the speaking voices you hear. Then tonight I want you to go home and read a passage into a tape recorder and evaluate your own voice. 21. What is the main point the professor makes? 这段文章主要讨论演讲者说话声音的三个要素：音量(volume)、音调(pitch)和语速(pace)，这三者决定着演讲效果的好坏。与之意思最接近的是选项B。

【正确答案】 C

【答案解析】[听力原文] According to the professor, what can a speaker do to keep an audience's attention? 音量、音调和语速这三个因素共同决定着演讲的效果，也就是说，它们都会对观众产生影响，只有选项C同时提到了这三项，因此选C。

【正确答案】 D

【答案解析】[听力原文] What recommendation does the professor make about volume? 在谈到音量时，教授建议演讲者不要依赖麦克风，因为一个优秀的演讲者是可以做到不用喊叫就大声演说的。可见，他认为喊叫是错误的做法。这道题根据常识也可以锁定正确答案D。

【正确答案】 A

【答案解析】[听力原文] According to the professor, how can a speaker indicate that the topic is about to change? 在讨论语速时，教授重点提到了停顿，由于停顿可以给听众思考时间，它也有助于从一个话题转换到另一个话题，所以这道题应该选A。

【正确答案】 D

【答案解析】[听力原文] What are the students going to use a tape recorder for? 在关于课堂授课内容的长篇讲话里，教授往往会在最后给学生布置作业，或者提到下一节课的内容等，考生应注意把握这一规律。这段讲话里，教授最后让学生回去后自己录一段录音，并对自己的声音进行评估，因此选D。