整数可以看作分母为1的分数，正整数、0、负整数、正分数、负分数_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题填空题

整数可以看作分母为1的分数，正整数、0、负整数、正分数、负分数都可以写成（）的形式。

答案

分数

阅读理解

阅读下面的短文，从文后方框中选择恰当的句子填入文中空白处

A. These countries are found in much of Africa, South America and parts of Asia.
B. These people don't have enough food to eat and they live in poor housing.
C. That may not

sound much, but it's about 14,000 people per hour.
D. But in the developing countries, many women have five or more children.
E. It could hurt the environment and increase the number of poor people.

     When you read this sentence, the population of the earth has grown by 10 people. (1)_____
     Most of these new people are born in developing countries. (2)_____
     In the developed countries of Europe and North America, the population is growing very slowly. This is because
women in these countries have, on average(平均), only one or two children. (3)_____
     In the developing countries, more than one billion people already live below the poverty line (贫困线).
     (4)_____ Children get little or no time at school and suffer from many kinds of diseases.
     The UN has said that the world's population will reach 12.5 billion people by the year 2100. If the number makes your
head spinning(眩晕), you're not alone. Many experts are worrying that so fast population growth could have very bad
results. (5)_____

推断题

我国古代人民在化学工艺方面作出了巨大贡献。在金属E和F中，金属E在春秋战国时期已开始生产和使用。下图是初中学过的常见物质的相互转化关系(部分产物图中已省略)。请根据图中的转化关系回答下列问题：

(1)写出红棕色粉末主要成分的化学式_________。

(2)A和B在自然界中发生化学反应生成的有机物为__________(化学式)。

(3)写出反应E→F的化学方程式_____________________。

(4)金属冶炼的难易程度与金属活动性有关。在金属E和F中，金属_______(填化学式)的冶炼和应用较早。