问题 选择题

如图所示是一种安装在自行车轮胎边缘用于照明的装置(俗称“电滚子”),内有磁铁与线圈.该装置是一个(  )

A.蓄电池

B.发电机

C.电容器

D.电动机

答案

“电滚子”内有磁铁与线圈,自行车行驶时,线圈切割磁感线,产生感应电流,用于照明,是一个发电机.

故选B

选择题
补全对话,情景问答

根据对话内容,在空白处填写适当的话语(话语可能是一个句子,也可能是一个短语或一个词),使对话完整。

(Thomas was very nervous before going to have a meal at his friend's house.)

Mr. Lee: Thomas, you look worried. 1.___________?

Thomas: I'm going to have a meal at a Korean friend's house and I don't know what I am supposed to do.

Mr. Lee: I have been to Korea twice and I know some Korean table manners.

Thomas: Oh, that's great! I've heard that it's OK to make noise when you eat in Korea.

Mr. Lee: I guess so, but it depends. When you eat 2.___________, for example, you have to make noise.

Thomas: What do you mean " have to"?

Mr. Lee: It's said that noodles taste better that way. It shows that you 3.___________.

Thomas: That sounds interesting.

Mr. Lee: At other times try to eat as quietly as possible. It's not polite to talk while chewing food.

Thomas: I see. 4. ____________?

Mr. Lee: Yes, they use chopsticks for most foods. But for rice and soups they use spoons. Remember:

              Never hold both at the same time.

Thomas: Is it OK that I eat the food fast and leave the table early?

Mr. Lee: Not at all. In Korean culture, older people are highly respected (尊敬), you must wait for the elders

             to hold their spoons first. And you should eat neither too fast nor too slowly. You should keep pace

            (速度) with the elders. When the elders finish the meal, you can get up together.

Thomas: Oh, that's quite different from ours. Thank you so much for 5.___________.

Mr. Lee: My pleasure. Please enjoy your meal.