采用高KV值X射线照相法的特点是什么？（）A、能获得较高的对比度 B、适用于厚试样或

根据短文内容，回答下列问题。

     Most new babies were born in the developing countries. These countries are found in Africa, South America

and parts of Asia. 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. In the

developing countries, many women have five or more children. In 1950, about one quarter of the world's

population lived in the developed countries. By 2050, these countries will be home to only about one tenth of the

world's people.

     In the developing countries, more than one billion people are still living below the poverty (贫困) line. These

people do not have enough food to eat and they live in poor housing conditions. Children get little time at school

and suffer (遭受痛苦) from many kinds of diseases.

     At the beginning of the 21st century, the world's population was around six billion. The U.N. has said that the

world's population will level off (平稳下降) at 12.5 billion by the year 2100. Other groups think the world's

population will continue to grow, reaching 14 billion before it becomes stable (稳定的), or even falls. 

1. In what areas of the world can developing countries be found?

   ________________________________________________

2. In 1950, what percent of the world's population lived in developing countries?

   ________________________________________________

3. How to describe the people who are living below the poverty line?

   ________________________________________________

4. There will be twelve and a half billion people on the earth in 2100, won't there?

   ________________________________________________

5. 将文中画线部分翻译成汉语。

   ________________________________________________

财政是国家凭借政治权力而进行的社会产品分配。财政的本质是[ ]

A、一种生产关系  

B、一种交换关系

C、一种分配关系

D、一种消费关系

冬天用煤火取暖时，容易使人中毒的是[ ]

A. 一氧化碳          

B. 二氧化碳          

C. 二氧化硫          

D. 碳氢化合物

以硫酸、氯磺酸或三氧化硫在液相磺化时一般用（）

A.釜式反应器

B.膜式反应器

C.气液鼓泡反应器

丙泊酚（异丙酚）的主要优点是（）。

A.苏醒迅速、完全

B.作用快而强

C.肝肾毒性小

D.可用于血卟啉症

E.血压下降不明显