问题 选择题

从下列实验事实所引出的相应结论正确的是[ ]

        实验事实                    结论

A.其它条件相同,Na2S2O3溶液浓度越大,  当其它条件不变时,增大反应物浓度化学反应速率加快

  析出硫沉淀所需时间越短

B.在化学反应前后,催化剂的质量和化学        催化剂一定不参与化学反应   

  性质都没有发生改变

C.  在常温下N2很难与金属化合            氮元素的非金属性很弱

D.   NaOH晶体不能导电                NaOH是非电解质

答案

答案:A

阅读理解

Two new studies suggest that modern running shoes could increase the risk of injuries to runners.

One study involved sixty-eight healthy young women and men who ran at least twenty-four kilometers a week. The runners were observed on a treadmill machine (跑步机). Sometimes they wore running shoes. Other times they ran barefoot (赤脚).

Researchers from the JKM Technologies company in Virginia, the University of Virginia and the University of Colorado did the study.

They found that running shoes create more stress that could damage knees, hips and ankle joints than running barefoot. They observed that the effect was even greater than the effect reported earlier for walking in high heels.

The study appeared in the official scientific journal of The American Academy of Physical Medicine.

The other study appeared in the journal Nature. It compared runners in the United States and Kenya. The researchers were from Harvard University in Massachusetts, Moi University in Kenya and the University of Glasgow in Scotland.

They divided the runners into three groups. One group had always run shoeless. Another group had always run with shoes. And the third group had changed to shoeless running.

Runners who wear shoes usually come down heel first. That puts great force on the back of the foot. But the study found that barefoot runners generally land on the front or middle of their foot. That way they ease into their landing and avoid striking their heel.

Harvard’s Daniel Lieberman led the study. He says the way most running shoes are designed may explain why those who wear them land on their heels. The heel of the shoe is bigger and heavier than other parts of the shoe, so it would seem more likely to come down first. Also, the heel generally has thick material under it to soften landings.

But the researchers do not suggest that runners immediately start running barefoot. They say it takes some training. And there can be risks, like running when your feet are too cold to feel if you get injured.

The study was partly supported by Vibram, which makes a kind of footwear that it says is like running barefoot. The findings have gotten a lot of attention. But the researchers say there are many problems in the way the press has reported in their paper. So they have tried to explain their findings on a Harvard Website.

小题1:What’s the main idea of the passage?

A.Walking in high heels could cause less serious effects than running barefoot.

B.Two new discoveries encourage people to run in high heels.

C.Running in shoes is partly good to runners.

D.Two new studies prove running without shoes is beneficial to runners in most cases.小题2:Which part of our body could be injured if we run in running shoes?

A.Toes.

B.Hips.

C.Feet.

D.Legs.小题3:What can we learn from the passage?

A.The way that we run by landing on the front or middle of our foot could avoid damaging our heel.

B.We should start running barefoot in no time.

C.Running in modern running shoes could cause more serious effects than running in high heels.

D.We won’t be injured if we run barefoot.小题4:What is the writer’s attitude towards the use of the modern running shoes?

A.Persuasive.

B.Negative.

C.Objective.

D.Supportive.

单项选择题