应用于药物利用研究的药物流行病学方法有 A．队列研究 B．个例报道 C．随机对照实验

已知A为淡黄色固体，T、R为两种常见的用途很广的金属单质，D是具有磁性的黑色晶体，C是无色无味的气体，H是白色沉淀。推断A—W物质各是什么，回答下列问题。

（1）写出下列物质的化学式：D：             N：             。

（2）A和水的反应属于下列何种反应类型         （填序号）。

A．化合反应       B．氧化还原反应     C．离子反应    D．置换反应

（3）若要确定E溶液中是否含有W物质，所选试剂为      （填序号）。

A．氯水和KSCN溶液          B．KSCN溶液

C．浓氨水                    D．酸性高锰酸钾溶液

（4）B与E混和得到H并在潮湿空气中变成M的过程中，可能观察到的现象：                                                ；

（5）B和R反应生成N的离子方程式：                                    ；

M→W的离子方程式：                                              ；

阅读理解。

    Plants and animals, including humans, need food and water to live on. These are from the natural resources

(资源) on Earth. To protect these resources, we need to keep the air clean and the water drinkable. We need

to keep the soil healthy. How do we do that?

* Protect the land

    The soil that covers fields and farms provides much of the food we eat. Human activities such as plowing (耕) fields, mining (采矿), and building highways can destroy (破坏) the land. Erosion happen when wind and

water carry away the soil. Soil erosion can turn rich farmland into a desert wasteland. So does this mean we

shouldn't build a highway or plow a field? Of course not. But it does mean we might think about Earth-friendly

ways of doing those things.

    Today farmers plow their fields in different ways to prevent erosion. They try to use less water for their

crops. They keep animals from eating the growing grass in just one area. Farmers also plant trees to prevent

erosion from happening.

* Save the Trees

    Another human activity that damages the land is deforestation (采伐森林). People take away a large number

of trees from a forest. Millions of square kilometers of forest disappear each year. When this happens, many

plants and animals lose their places to live. They may die out, or become very few. Scientists haven't even

discovered all the living things in the forest. We may be losing some without even knowing they are there.

Trees absorb (吸收) and use carbon dioxide (二氧化碳) when they make food. Environmentalists encourage

careful management of the forests. They ask people to replant trees after they cut down the forest. 

* Recycle, Reuse, Reduce

     People throw a piece of paper into the wastebasket after using it. The paper becomes trash. Where does

the trash go next? Much of our trash ends up in landfills (垃圾填埋地). They take up valuable land and

sometimes pollute the water, air, and land around them. More than a third of the trash in landfills is paper.

Recycling, reusing, and reducing what you throw away can cut down on the need for more landfills. In fact,

we can recycle about eighty percent of household trash.

1. What does the underlined word "erosion" mean? [ ]

A. Plowing fields and mining.

B. Cutting down trees and farming.

C. Wind and rain carrying away soil.

D. Building highways on the farmland.

2. How do farmers prevent erosion now? [ ]

A. They try to use more water for their crops.

B. They stop animals from eating the growing grass in just one area.

C. Farmers also plant flowers to prevent erosion from happening.

D. They move to another place.

3. Why do we need to save the trees? [ ]

A. To discover more new trees every year.

B. To make more money.

C. To take away a large number of trees from the forest.

D. To keep good places for animals and plants to live in.

4. How much of the trash can we recycle? [ ]

A. All the trash.

B. Very little.

C. One third.

D. Four fifths.

5. What's the purpose of the author writing the passage? [ ]

A. To ask people to look for places to plant trees.

B. To tell people how to protect natural resources.

C. To show how the lands are destroyed by people.

D. To discuss ways of protecting animals and plants.

常规清收方式不包括( )。

A．直接追偿

B．委托第三方清收

C．协商处置抵质押物

D．财产保全

为什么提升机严禁用常用闸进行紧急制动？

心气虚的表现为

A．心悸气短，面色苍白
B．心悸气短，眩晕健忘
C．心悸气短，胸闷汗出
D．心悸气短，胸闷疼痛
E．心悸气短，失眠多梦