题目内容：

Everyday we go to school and listen to the teacher, and the teacher will ask us some questions. Sometimes, the classmates will ask your opinions of the work of the class. When you are telling others in the class what you have found out about these topics, remember that they must be able to hear what you are saying. You are not taking part in a family conversation or having a chat（闲谈）with friends—you are in a slightly unnatural situation where a large group of people will remain silent, waiting to hear what you have to say. You must speak so that they can hear you—loudly enough and clearly enough but without trying to shout of appearing to force yourself.

Remember, too, that it is the same if you are called to an interview whether it is with a professor of your school or a government official who might meet you. The person you are seeing will try to put you at your ease（轻松）but the situation is somewhat（一点儿）different from that of an ordinary conversation. You must take special care that you can be heard.

48. When you speak to the class, you should speak ________.

A．as loudly as possible          B．in a low voice

C．loudly                      D．forcefully

49. Usually, when you speak to the class, the class is __________.

A.noisy    B．quiet     C．having a rest    D．serious

50.The situation in the class is ________ that in your house.

A．not very different from           B．sometimes the same as

C.．sometimes not the same as        D．not the same as