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问题 问答题 简答题

饱和蒸汽能否代替过热蒸汽水样？为什么？

答案

参考答案：

不能，原因如下：

（1）两者所含成分相差很大，过热蒸汽是单相介质，没有水分；饱和蒸汽中盐类、水分较多，且分布不均匀。若代替，则容易引起误判断，导致操作错误。

（2）不利于准确判断因减温水水质劣化引起的蒸汽品质劣化原因。

（3）不能判断饱和蒸汽在过热器中的盐类沉积量。

填空题

_______为小儿结核的首选药物。
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单项选择题

Many animals recognize their food because they see it. So do humans. When you see an apple or a piece of chocolate you know that these are things you can eat. You can also use other senses when you choose your food. You may like it because it smells good or because it tastes good. You may dislike some types of food because they do not look, smell or taste very nice. Different animals use different senses to find and choose their food. A few animals depend on only one of their senses, while most animals use more than one sense.

Although there are many different types of food, some animals spend their lives eating only one type. The giant panda(大熊猫) eats only one particular type of bamboo(竹子). Other animals eat only one type of food even when given the choice. A kind of white butterfly(蝴蝶)will stay on the leaves of a cabbage, even though there are plenty of other vegetables in the garden. However, most animals have a more varied diet(多样化饮食). The bear eats fruits and fish. The fox eats small animals, birds and fruits. The diet of these animals will be different depending on the season.

Humans have a very varied diet. We often eat food because we like it and not because it is good for us. In countries such as France and Britain, people eat food with too much sugar. This makes them overweight, which is bad for their health. Eating too much red meat and animal products, such as butter, can also be bad for the health. Choosing the right food, therefore, has become an area of study in modern life.

Which of the following eats only one type of food（）

A．The white butterfly.

B．The small bird.

C．The bear.

D．The fox.
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