题干

科学研究中,往往需要借助一定的工具进行准确测量.下列实验过程中均需要测量,其中不需要计算平均值的是(   )

A:测定胸围差

B:测定某种食物中的能量

C:测定反应速度

D:探究花生种子大小的变异

上一题 下一题 0.0难度 选择题 更新时间:2010-05-15 12:44:32

答案(点此获取答案解析)

A

同类题1

Fill in the blanks according to the passage .Only one word for each blank.

    Once upon a time, there was a millionaire who loved money more than the other things in the world. He didn't know exactly how much he had, so he took on a little girl to count all his money for him.

    It took the little girl six days to count all the money. When she told the millionaire that he had forty-two million dollars, he was wild with joy and asked, “How much money do you want?” He thought she was only a child and he could give her less money.

    The girl said, “Well, I worked for six days, so I think you should pay me for six days. Give me two pennies for the first day. Each day after that, just give me the amount you give me the day before, multiplied(乘) by itself.”

    The millionaire thought that in this way he would only have to give her a few dollars. What a foolish girl!

    On the first day the millionaire paid her two pennies, and on the second day, two pennies times two pennies, or four pennies.

    Each day after that, he gave her the number of pennies he had given her the day before, multiplied by itself. And by the sixth day the foolish millionaire had to give the clever girl all his money.

    Long long ago, a millionaire loved money than anything ____ in the world. One day he took on a girl to count his money. The girl spent six days in ____ his money. The millionaire asked the girl how much money he should ____ for what she did. The girl answered he should give her the amount he gave her the day before, multiplied by itself.

    The millionaire ____ with the girl. He thought the girl was a ____. In fact, the girl was so clever. The millionaire had to give the clever girl all his money.

同类题2

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Tired of traditional running? Well, maybe it's time to try using your hands instead. That's what Shaun McCarty and other Australians are doing — running on all fours. ____

    McCarthy, who comes from Melbourne, Australia, said he's the one behind the term “crunning.” “It's not crawling, it's not running.” he said. “Crunning is a better workout than running. It puts more of an emphasis(着重)on the body than traditional running does. ____ ”

    McCarthy thinks that he gets much more exhausted after crunning, so he believes it must burn more calories than running.

     ____ Some believe crunning could result in bad shoulder injuries or broken noses.

    But McCarthy is not worried. Many Melbourne residents have been seen running around on all fours. ____ In the Chinese city of Zhengzhou, crawling, a much slower version of crunning, has been a favourite activity for many years. According to some people there, the exercise is believed to date back two thousand years to the Han Dynasty.

     ____ Then McCarthy advises you to buy some good shoes, hand gloves and most important of all, a face mask!

A. Ready to give crunning a try?

B. As it turns out, they are not the only ones.

C. Crunning seems more difficult than traditional running.

D. It really exercises your legs and shoulders at the same time.

E. It's part of the Internet's latest fitness activities: “Crunning.”

F. However, many are not sure if it is the right exercise for humans.

G. He warns, however, that he can't say whether crunning is potentially harmful.