What is the first thing you want to do when you see someone yawn（打哈欠）？You want to yawn to

问题补充：

What is the first thing you want to do when you see someone yawn（打哈欠）？You want to yawn, too! Yawning is contagious.

Scientists have found that all people yawn. Babies start to yawn even before they are born. The earliest yawn takes place when a baby is still inside its mother. When young children are about one year old, they start to yawn when they see others yawning. That’s why scientists seem to think yawning is contagious.

It’s no secret that yawning is contagious, but why do we yawn? Well, scientists are not really sure.

Some think we yawn because we feel bored. Recently scientists studied two groups of students between the ages of 17 and 19. One group watched music videos, and the other watched a boring color test. Scientists compared the numbers of their yawns and found that the color test group yawned more times than the video group.

Another reason for yawning has to do with breathing. Some scientists believe that when we are bored or tired, we breathe more slowly. As our breathing slows down, we cannot get rid of （去除）enough carbon dioxide, our bodies will tell the brains（大脑）to breathe deeply. The result is a big yawn.

In , scientists suggested a new reason. They said that the reason why people yawned was to cool down their brains. These scientists found that people who were warmer than others yawned more often.

Scientists are still trying to find out why yawning happens and why it is so contagious. But they are only sure that when one person yawns, almost everyone else nearby wants to yawn, too.

【小题1】The underlined word “contagious” in Paragraph 1 means .A．helpful to our healthB．passing from one person to anotherC．hard to understandD．getting into one trouble after another【小题2】According to the scientists, people start to yawn when they are .A．bornB．one year oldC．17 or 19 years oldD．inside their mothers【小题3】Which of the following are the possible reasons for yawning according to the passage?

①People yawn because they are bored

②People yawn to catch others’ attention

③People yawn to cool down their brains

④People yawn to get rid of carbon dioxide.A．①②③B．②③④C．①②④D．①③④【小题4】We can probably read this passage in a A．storybookB．travel guidebookC．movie posterD．science magazineB

答案：

(答案→)B

解析：本文叙述了当你看见某人打哈欠的时候你第一件事想要做什么？打哈欠是传染的。但是科学家们还没有找到原因，只知道一个人打哈欠，他附近的人也想打哈欠。

【小题1】语意猜测题。根据对第一段内容的理解，可知划线部分的意思是从一个人传到另一个人，故选择B。

【小题2】细节理解题。根据第二段内容The earliest yawn takes place when a baby is still inside its mother.可知选择D。

【小题3】细节理解题。根据对整篇文中的理解，可知人们打哈欠是因为他们感觉累；使他们的大脑冷静下来；并且排除二氧化碳，故选择D。

【小题4】细节理解题。根据对这篇文章的理解，可知我们可能在科学杂志是上读到。故选择D。