甲、乙两质量分布均匀的物体的体积相同，他们的质量之比是5：3，_爱下问搜题

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问题填空题

甲、乙两质量分布均匀的物体的体积相同，他们的质量之比是5：3，则它们的密度之比是______，若甲截去

3

5

，乙截取

5

7

，则甲、乙两物体剩下部分的密度之比______．

答案

∵V_甲=V_乙，m_甲：m_乙=5：3；

∴ρ_甲：ρ_乙=

m甲

V甲

：

m乙

V乙

=

m甲

m乙

×

V乙

V甲

=

5

3

×

1

1

=

5

3

；

又∵密度是物质本身的一种属性，与质量、体积无关，

所以若甲截去

3

5

，乙截取

5

7

后，剩下部分的两物体密度之比仍为5：3．

故答案为：5：3，5：3．

完形填空

Red is the color of China. Among all the colors, red is most   16 seen. The color red is fresh and pure, and in China we call it China Red. Chinese people are attracted by the color red not only because it makes people excited, but also because it has   17  meaning in Chinese culture and history.
No country in the world has ever   18  a color in such a way as China. Here, red is a symbol. It gives color to the soul (灵魂) of the nation. In the past, red represented dignity (尊严) and mystery. Even now, Chinese people   19  the color much more than the rest of the world does. It can be said that China Red is an everlasting theme for China, and an important color for the Chinese people. China Red has   20  a very popular phrase, attracting the world’s attention.
Finding red-colored things in China is very   21 , as you can see the color everywhere. All traditional red things have played special roles in China. Things like the walls of ancient palaces, the   22  flag, Chinese knots, lanterns, traditional paper-cuts, and even tanghulu are all red.
Red is the color of   23 , health, harmony, happiness, peace, wealth and so on. Only real things and events can fully   24  red’s real beauty. The color can be alive and breathing only when it’s connected with people.
In China, red is more than just a color. It carries the ancient history and   25  of the Chinese nation. China Red is filled with mysterious charm beyond description and it is right here in China waiting for you to feel and discover!

B．international

问答题简答题

民间鉴别毒菌的方法常有哪些？