问题 单项选择题

城市生态系统能量流动具有的特征不包括()。

A.在能量使用上,能量来源不仅仅局限于生物能源,还包括大量的非生物能源

B.在传递方式上,城市生态系统的能量流动方式要比自然生态系统少

C.能量在流动中不断有损耗,不能构成循环,具有明显的单向性

D.除部分能量是由辐射传输外(热损耗),其余的能量都是由各类物质携带

答案

参考答案:B

解析:

本题的考点是城市生态系统能力流动的特征。城市生态系统能量流动具有以下特征。

(1)在能量使用上,能量来源不仅仅局限于生物能源,还包括大量的非生物能源。

(2)在传递方式上,城市生态系统的能量流动方式要比自然生态系统多。

(3)在能量流运行机制上,自然生产系统能量流动是自发的,而城市生态系统能量流动以人工为主,如一次能源转换成二次能源、有用能源等皆依靠人工。

(4)能量流动在流动中不断有损耗,不能构成循环,具有明显的单向性。

(5)除部分能量是由辐射传输外(热损耗),其余的能量都是由各类物质携带。

多项选择题
阅读理解

Volunteering can help you deal with stress and problems, have more confidence, and introduce you to exciting new ideas and people. But what kind of volunteering should you do?

Firstly, think about what you enjoy. What are you interested in? What do you want to be when you grow up? For example, if you love animals, you can volunteer to care for abandoned(被遗弃的) pets or injured wildlife. If you want to grow up to be a doctor or a nurse, you can look for a youth volunteer program at a local hospital.

Secondly, think about what you’re good at. What skills do you have? What kinds of jobs do you do best? Try to find a volunteer position that will let you make the most of your strengths and talents. For example, if you’re a great speaker, then you could try educating others about a problem you care about. If you’re a cook, you might find a way to help feed hungry people in your area.

Thirdly, look for what your own community needs. What should be improved in your town, city, or school? What types of volunteer projects would do the most good? For example, if there are a lot of homeless people in your area, you could raise money to help them. If your town has empty areas filled with dirt or rubbish, you could organize or join a group to plant trees and flowers to make these areas more attractive.

The problems of the world, or even just of your community, might seem gigantic. Some people might even feel like there’s no point trying to do anything, since what they can contribute seems so small. But every person is important, and can do some good and make a difference. Like you!

小题1:What is the text mainly about?

A.How to be a good volunteer.

B.What we can do when we grow up.

C.What kind of volunteering one can do.

D.How to improve society by volunteering.小题2:The text does NOT mention _____ as a basis for volunteering. 

A.interests

B.abilities

C.people’s needs

D.what one gets in return小题3:The word “gigantic” in the last paragraph can be replaced by “_____”.

A. huge     B. serious    C. meaningless   d. different

小题4:How is the text mainly developed?

A.Through reasoning.

B.Through similarities.

C.Through examples.

D.Through explanations.