【正确答案】
B、D
【答案解析】teacher： Ailie, you are appointed to deliver a lecture to the class next week, so make a good preparation for it.
student： I will. But Professor Webber, since it is my first time to give a speech in front of the class, I really have no idea about it.
teacher： Don’t worry. I will give you a hand. Generally, there are several types of lectures: the oral essay, multimedia lecture, and the participatory and problem solving lectures.
student： Then which one should I choose?
teacher： The first two are more lecturer-controlled and closer to the traditional model wherein a lecture is divided into different topics or sub-topics and systematically covered. The participatory and problem-solving varieties operate with apparently greater flexibility, but in reality demand more planning if it is not to get out of hand.
student： So I'd better choose one from the first two types?
teacher： Yeah, I think it is much easier for you.
student： Then comes the length, how long should the lecture be?
teacher： It needn't to be too long. A short lecture will be OK. From my personal experiences, I find 30 to 40 minutes the maximum before people start to glaze over.
student： OK, I see. Not to exceed the maximum time limit. Thank you, professor.