问题 选择题

下列现象属于液化的是(  )

A.冰雪消融

B.衣柜中的卫生球变小

C.从冰箱中拿出的冰棒冒“白气”

D.日光灯用久后两端变黑

答案

A、冰雪是固态的,消融是变为了液态的水,固态变为液体的现象叫熔化;

B、卫生球变小就是变为了气态,固态变为气态的现象叫升华;

C、“白气”是液态的,是由空气中的水蒸气遇到比较冷的冰棒形成的,气态变为液态的现象叫液化;

D、白炽灯的灯丝在使用时的温度很高,会升华为气态的钨蒸气,关掉灯后,钨蒸气又会遇冷凝华为固态的钨,凝结在灯泡内壁上.

故选C.

阅读理解

阅读理解。

     As everybody knows, tourism plays an important part in the development of a country's economy, the life

of the nation and international cooperation. Individually, it can enlarge our personal perspective and knowledge,

and make us feel good.

     However, tourism can also lead to pollution and the destruction of places of interest, which is difficult to

avoid.

     Fortunately, "Green Tourism" is now being promoted and developed all over the world. As time goes by,

people will begin to realize the importance of these places of interest. "Green Tourism" teaches people to love

nature more and to consciously protect it by enjoying its beautiful scenery and learning more about it. "Green

Tourism" is the best kind of tourism as its purpose is to appreciate and research natural environments including

wild plants and animals, and of course the cultures of many places.

     Compared with traditional tourism, the main characteristic (特色) of "Green Tourism" is learning more

about nature and people. Traditionally, people travel the world to amuse themselves and pass time pleasantly.

But "Green Tourists" are different. They travel because they are attracted by the characteristics of protected

areas. They want to make good use of natural resources but not use them up. For example, they research the

wildlife, the culture and the customs or a place so that they can learn more about the history and value of the

area.

     In short, "Green Tourism" has a purpose and a plan, but not to pollute or destroy our places of interest.

1. What would be the best title for the text?

A. Green Tourism

B. The Difference between Green Tourism and Traditional Tourism

C. Travel Habits Are Changing

D. How to Have a Good Journey

2. The underlined word "promoted" in the third paragraph probably means ____.

A. raised

B. pushed

C. encouraged

D. advanced

3. Which of the following is NOT the difference between Green Tourism and Traditional Tourism?

A. Green Tourism can enlarge people's personal perspective and knowledge and make them feel good.

B. The main characteristic of Green Tourism is learning more about nature and people.

C. Traditional tourism is to amuse people themselves and make them pass time pleasantly.

D. Traditional tourism can lead to more pollution and the destruction of places of interest than Green Tourism.

4. From the passage we know that the author is most probably ____.

A. a supporter of tourism

B. a supporter of Traditional Tourism

C. a supporter of Green Tourism

D. a lover of tourism

单项选择题