问题 单项选择题

关于月经周期中雌激素的变化,下列正确的是()

A.排卵前形成第一高峰

B.排卵后10日形成第二高峰

C.第一高峰较平坦,峰的均值低于第二高峰

D.黄体萎缩时,雌激素水平缓慢下降

E.月经血净后雌激素达最低水平

答案

参考答案:C

阅读理解

阅读理解。

     Why do we need to throw less away? There are two reasons. One is that some resources (资源) are

nonrenewable (不可再生的). That means there is only a certain amount of that resource in the world.

One example of this is oil. When we use up all the oil in the world, there will be no more.

     There is another reason for throwing less away. All of our trash has to be put somewhere. Often, it is

put into garbage dumps (垃圾场). Much of that trash will be there for hundreds of years. The dumps will

be filled up with all this trash.

     There are three ways to cut down on trash.

     One way is to recycle. When you recycle something, it means it is made into another shape and used

again. Old newspaper may become paper bags. A glass jar can be melted (熔化) and made into a bottle.

     Another way to cut down on trash is to reuse things. You can wash and use again a bottle that can hold

mustard (芥末酱) or something else.

     The third way to cut down on trash is to reduce the amount of trash you make, stop buying thing that

you don't need in the first place. That reduce the amount of the earth's resources that you use.

1. How many reasons do we need to throw less away?

A. Three

B. five

C. two

2. When you reuse something, it means _____.

A. it is made into another shape and used again

B. it is used again

C. it isn't used any more

3. All the ways of cutting down on trash in the passage are to _____.

A. recycle and reuse things

B. recycles and reduce the amount of trash you make

C. reuse things recycle and reduce the amount of trash you make

4. If a broken plastic box is changed into a plastic ruler, the way is to _____.

A. recycle

B. reuse

C. reduce 

5. The word "reduce" in the passage means _____.

A. 还原

B. 减少

C. 增加

单项选择题