函数f（x）是上的增函数，若对于x1，x2∈R都有f（x1）+f（x2）≥f（-

电话交换使用的是（）交换方式，另外，还出现了适合进行数据交换的（）交换方式和可以承载综合业务的ATM交换方式。

Many people believe that teaching children music makes them smarter, better able to learn new things. But the organizers of a new study say there's no scientific evidence that early musical training affects the intelligence of young people.

An estimated 80 percent of American adults think music lessons improve children's abilily to learn or their performance in school. They say that the satisfaction for learning to play a new song helps a child express creativity.

Researchers at Harvard University, however, have found that there's one thing musi­cal training does not do. They say it does not make children more intelligent. Samuel Mehr is a graduate student at Harvard's School of Education. He said it is wrong to think that learning to play a musical instrument improves a child's intellectual development. He says the evidence comes from studies that measured the mental ability of two groups of 4-year-olds and their parents. One group attended music class, the other went to a class that places importance on the visual arts—arts that can be seen.

"The evidence there is 'no'. We found no evidence for any advantage on any of these tests for the kids participating in these music clases," said Mehr.Samuel Mehr says researchers have carried out many studies in an effort to learn whether musical training can make children smarter. He says the results have been mixed. He says only one study seems to show a small percentage increase in IQ, intellectual scores among students after one year of music lessons. He does not believe that IQ is a good measure of child's intelligence. He says researchers in his study compared how well children in the musical training group did on mental processing tasks or projects, then the results were compared to those of children who did not take lessons. There was no evidence that the musical training group did much better on the mental tasks than the other group.

The researchers comfirmed the results with a larger group of children and their par­ents.Mr Mehr says music lessons may not offer children a fast easy way to gain entry to the best schools later of their life. But he says the training is still important for cultural reasons. In his words, "We teach music because music is important for us."

小题1:According to the new study, musical training______.

A．makes children smarter

B．helps a child express creativity

C．does not make children more intelligent

D．improve children's ability to learn in school小题2:Samuel Mehr may agree that______.

A．the children who attended music class are smarter than those who attended arts class

B．IQ is a good measure of a child's intelligence

C．we needn't to teach children music

D．music training is still important for cultural reasons小题3:In order to confirm his view, Samuel Mehr______.

A．conducted more than one research

B．interviewed many American adults

C．taught two groups of 4-yetr-olds music and arts

D．offered children a fast way to be admitted to the best schools小题4:The artical may be taken from a report about _____.

A．health

B．education

C．culture

D．economy

社会主义核心价值观的“三个倡导”，分别从国家、社会和个人三个层面进行概括，就是倡导（）①富强、民主、文明、和谐②自由、平等、公正、法治③自由、平等、博爱、包容④爱国、敬业、诚信、友善

A.①②③

B.①②④

C.①③④

D.②③④

一桁架及其承载情况如图，三杆的抗拉（压）刚度EA相同，则其中杆BD的轴力N为（）。

A．N=P

B．N＞0

C．N＜0

D．N=0

根据原文，下列表述不属于磁共振成像原理内容的一项是：

A．在磁场旋转的原子核可以吸收频率与旋转频率相同的电磁波，使原子核的能量增加。

B．许多疾病的病理过程会导致水分变化，而这种变化恰好能在磁共振图像中反映出来。

C．在磁场旋转的原子核恢复原状当时，就会把多余的能量以电磁波的形式释放出来。

D．分析被电磁波照射后的原子核所释放出来的电磁波，就可得知该原子核的位置和种类。