问题 问答题

锅炉对蒸汽品质有何要求?

答案

参考答案:

所谓蒸汽品质是指蒸汽的纯洁程度。通常用单位质量蒸汽中所含杂质的问题来表示。蒸汽中的杂质为各类盐、碱和氧化物,其主要部分是盐类,故常把蒸汽对杂质的携带称为蒸汽带盐。蒸汽含盐量越多,蒸汽品质越差。因此电站锅炉对饱和蒸汽的品质和过热蒸汽的品质都有相关的规定要求。

阅读理解

阅读理解。

      Until recently we had been living in the Yukon Territory in Canada, in a town seventy miles or so of the

Arctic Circle. It is romantically called "The Land of the Midnight Sun" because during the summer the sun

shines continuously, even at midnight. On the other hand, it is also called "The Land of Darkness" because

in winter the opposite happens. 

       My classmates probably thought I liked to tell tales when I said I had to walk to school on a river in my

hometown. But it was true.

       When the darkness comes, so does the cold, because there is no sun to give warmth. The land becomes

a world of ice and snow. The few roads that link villages are completely (完全地) covered with snow; people

must travel on frozen rivers. If they do not have far to go, they put on snowshoes. These shoes prevent them

from sinking into the thick snow. However, if they have a long journey to make they ride in dog sleds. 

       Rivers are very important to the people of the Yukon. When summer comes and the sun once more shines

upon the land, the rivers become moving highways suitable for boats and canoes. 

       Of course, another important means of transportation for all of us in the village was the plane, which

provided us with the only means of getting to the outside world.

1. Which of the following in NOT true according to the passage? [ ]

A. The Yukon Territory is in Canada.

B. Dogsleds are used for long journeys.

C. Winter is longer than summer in Yukon.

D. Planes are the only link with the outside world.

2. The underlined part in paragraph 2 means that my classmates _____ we walked to school on a river.[ ]

A. thought I liked telling tales when

B. felt excited when they learned that

C. thought I had a hard time when

D. thought it was unbelievable that

3. What is the main topic of the passage?[ ]

A. How to walk on a river in winter.

B. How the Yukon people travel.

C. The importance of planes in the Yukon.

D. The weather inside the Arctic Circle.

填空题