2019学年度人教版选修八Unit3Period2Language points 阅读学案

Ⅰ. 阅读理解

　　Years ago we said that LEDs would be something in the future. But as time goes on, LEDs have become the present because of rapidly falling prices and improving quality. We've firmly entered the LED period, as Lyoyd showed with his experience of changing 100% of his lights to LEDs.

　　The physics Nobel Prize in 2014 was given to three well-known Japanese scientists-Isamu Akasakl, Hiroshi Amano, and Shuji Nakamura-who invented the blue Led and made LEDs truly reach their potential as a mass-market light source.

　　As we can know, LEDs take the lead in the competition when it comes to efficiency(效率). Most LED lights that you can buy right now can't reach the 300 watt shown here, but this is what we know it can be achieved, and over the coming years we should gradually more closer to that goal.

　　Why was blue so important? Because without it, we couldn't make high quality white light from LEDs. Red and green LEDs have been around for a long time but blue was really missing. Thanks to the blue LED we now can get white light sources which have very high energy efficiency and very long lifetime.

　　With good use of LEDs, the world's electricity used for lighting can be reduced greatly. But energy-efficiency isn't the only thing. Material efficiency is also very important for LEDs. A LED can last up to 100, 000 hours, compared to 10, 000 hours for fluorescent(荧光)lights and 1, 000 for incandescent bulbs(白炽灯泡). This means that only a small part of the bulbs need to be produced over time. That can greatly reduce the costs. Using LEDs, the quality of lights is also improved, so that people can better see when they're out at night.

【语篇概述】本文主要讲的是LED灯的发明以及它的优点。

1. Why did the author mention Lyoyd's experience?

A. To compare the prices of lights.

B. To describe the history of LEDs.

C. To tell us LEDs are still on the way.

D. To show the LEDs period has come.

【解析】选D。细节理解题。根据第一段最后两句可知Lyoyd把他所有的电灯都换成了LED灯的经历告诉我们LED时代到来了。

2. We can get white from_______.

A. red LED　 B. blue LED

C. green LED　 D. orange LED

【解析】选B。细节理解题。根据第四段中Thanks to the blue LED we now can get white light sources可知我们可以从蓝光LED灯中得到白色光源。

3. What can we know about LEDs?

A. They first appeared in Japan.

B. They have taken the place of other lights.

C. They can reach beyond the 300 watt at present.

D. The inventors of blue LED won the Nobel Prize.