实现社会扩大再生产的根本途径是( )。A．经济建设B．投资建设C．民用建设D．工程

在光滑的绝缘水平面上，有一个正三角形abc，顶点a、b、c处分别固定一个正点电荷，电荷量相等,如图所示，D点为正三角形外接圆的圆心，E、G、H点分别为ab、ac、bc的中点，F点为E点关于c .电荷的对称点，不计空气阻力。下列说法中正碑的是

A．D点的电场强度为零、电势可能为零

B．E、F两点的电场强度等大反向、电势相等

C．E、G、H三点的电场强度和电势均相同

D．若释放c电荷，c电荷将一直做加速运动

If you want to stay young, sit down and have a good think. This is the research finding of a team of Japanese doctors, who say that most of our brains are not getting enough exercise and, as a result, we are growing old unnecessarily soon.

Professor Taiju Matsuzawa wanted to find out why quite healthy in northern Japan appeared to be losing their ability to think and reason at a rather early age, and how the speed of getting old could be slowed down.

With a team of researchers at Tokyo National University, he set about measuring brain volumes of a thousand people of different ages with different jobs. Computer technology helped the researchers to get most exact measurements of the volume of the front and side parts of the brain, which have something to do with intellect and feelings, and decide the human character. As we all know, the back part of the brain, which controls task like eating and breathing, does not contract with age.

Contraction of front and side parts—as cells die off—was seen in some people in their thirties, but it was still not found in some sixty and seventy-year-olds.

Matsuzawa concluded from his tests that there is a simple way to prevent the contraction—using the head.

The findings show that contraction of the brain begins sooner in people in the country than in the towns. “Those with least possibility,” says Matsuzawa, “are lawyers, followed by university professors and doctors. White collar workers doing the same work day after day in government offices are, however, as possible to have contracting brains as the farm worker, bus driver and shop assistant.”

小题1:The team of doctors wanted to find out _____.

A．at what point people grow mentally old

B．how to make people live longer

C．the size of certain people’s brains

D．which people are the most clever小题2:Their research findings are based on _____.

A．an examination of farmers in northern Japan

B．tests given on a thousand old people

C．examining the brain volumes of different people

D．using computer technology小题3:The doctors’ tests show that _____.

A．our brains contract as we grow older

B．one part of the brain does not contract

C．sixty-year-olds have better brains than thirty-year-olds

D．some people’s brains have contracted earlier than other people’s小题4:The most possible conclusion of the passage is that _____.

A．most of us take more exercise

B．it’s better to live in the town

C．the brain contracts if it is not used

D．the more one uses his brain, the sooner he becomes old

如果窗宽为200，下界CT值是OHu，那么（）

A.上界为100Hu

B.上界为200Hu

C.上界为-200Hu

D.上界为-100Hu

E.上界为-300Hu

在C语言中，形参的缺省存储类是

A．auto

B．register

C．static

D．extern

下列关于脊柱出现的重要意义的叙述中，不正确的是（）。

A.脊柱有强大的支持作用

B.脊柱可使身体呈纺锤形

C.脊柱可成为运动的支架

D.脊柱有保护脊髓的功能