【解析】选D。推理判断题。根据第二段可知蓝光LED的发明者获得了2014年诺贝尔物理奖。

4. What does the last paragraph mainly talk about?

A. The costs of LED lights.

B. The lifetime of LED lights.

C. The advantages of LED lights.

D. The material efficiency of LED lights.

【解析】选C。主旨大意题。最后一段主要讲的是LED灯的能效高, 使用寿命长, 也就是LED灯的优点。

　　We all know what a brain is. A doctor will tell you that the brain is the organ of the body in the head. It controls our body's functions, movements, emotions and thoughts. But a brain can mean so much more.

A brain can also simply be a smart person. If a person is called brainy, he is smart and intelligent. If a family has many children but one of them is super smart, you could say"He's the brains in the family. "And if you are the brains behind an organization, you are responsible for developing or organizing it.

Brain trust is a group of experts who give advice. Word experts say the phrase"brain trust"became popular when Franklin D. Roosevelt first ran for president in 1932. Several professors gave him advice on social and political issues facing the U. S. These professors were called his"brain trust".

These ways we use the word"brain"all make sense. But other ways we use the word are not so easy to understand. For example, to understand the next brain expression, you first need to know the word"drain". As a verb, to drain means to remove something by letting it flow away. So a brain drain may sound like a disease where the brain flows out the ears. But, a brain drain is when a country's most educated people leave their countries to live in another. The brains are, sort of, draining out of the country.

However, if people were responsible for a great idea, you could say they brainstormed it. Here, brainstorm is not an act of weather. It is a process of thinking creatively about a complex topic. For example, business leaders may use brainstorming to create new products, and government leaders may brainstorm to solve problems.

If people are brainwashed, it does not mean their brains are nice and clean. To brainwash means to make someone accept new beliefs by using repeated pressure in a forceful or tricky way. Keep in mind that brainwash is never used in a good way.

【语篇概述】本文讲述"brain"这个单词在日常生活中的一些特殊的含义。

5. Why did Roosevelt successfully win the election according to the passage?

A. Because he was the brain trust of Americans.

B. Because he got his brain trust.

C. Because he was smart at giving advice.

D. Because word experts say he is"the brain trust".

【解析】选B。细节理解题。根据第三段"Several professors gave him advice on social and political issues facing the U. S. These professors were called his'brain trust'".