问题 选择题

下列关于世界人口增长分析叙述,错误的是[ ]

A.世界人口的增长速度大体是先慢后快

B.世界人口的增长速度大体比较均匀

C.世界人口每增长10亿人,所用的时间越来越短

D.人口增长过快会给社会带来许多问题

答案

答案:B

单项选择题
单项选择题

A

Ask Dr Jeffers.

This month Dr. Jeffers is answering questions about human brain and how it works. Dear Dr. Jeffers,

One of my colleagues, Felix Moeller, told me that scientists are learning to use computer to ’read minds’. Is there any truth to this story

--Jane Leon, New York, USA

Dear Ms. Leon,

Well, a lot of research is being conducted in this area, but so far, the brain scanning equipment and corresponding computer programs haven’ t been able to actually read thoughts. In one experiment, test subjects(受试者) were connected to scanning equipment and shown two numbers on a screen. They were then asked to choose between adding or subtracting(减)the two numbers. Using this method, researchers were able to follow brain processes and make the correct assumptions (假 设) 70 percent of the time. It’ s not quite mind reading, but it’ s certainly a first step.

--Dr. J.

Dear Dr. Jeffers,

My three-year-old son loves it when I dig my fingers into his sides and tickle (胳肢)him until he laughs uncontrollably. The other day I noticed him trying to tickle himself but he couldn’t do it. Why not

--Glenn Lewis, Vancouver, Canada

Dear Mr. Lewis,

It’s because of how the brain works. The brain is trained to know what to pay attention to and what to ignore. It causes us to ignore physical feelings we expect to happen, but it causes a mild panic reaction when there is an unexpected feeling. For example, you don’ t notice how your shoulder feels while you’ re walking down the street. But if someone comes up behind you and touches you lightly on the shoulder, you may jump in fear. It’ s that unexpected part that causes the tickle reaction.

--Dr. J.

People laugh when tickled by others because the feeling is().

A. unexpected

B. expected

C. comfortable

D. uncomfortable