练习

【练习】

Most people would describe water like a colorless liquid. They __1

would know that in very cold conditions it becomes a solid called
ice and that when heating on a fire it becomes a vapor called steam. __2

However, water, they would say, is a liquid. We have learned that
water consists of molecules composed with two atoms of hydrogen __3

and one atom of oxygen, which we describe by the formula H2O.
This is equally true of the solid called ice and the gas called steam.

Chemically there is no difference between the gas, the liquid, and
the solid, all of which is made up of molecules with the formula H2O. __4

This is true of other chemical substances; most of them can exist as
gases or as liquids or as solids. We may normally think of iron as a
solid, but if we will heat it in a furnace, it will melt and become a __5

liquid, and at very high temperatures it will become a gas. Nothing
very permanent occurs when a gas changes into a liquid or a solid.

Everyone knows that ice, which has been made by freezing water,
can be melted again by warmed and that steam can be condensed __6

on a cold surface to become liquid water. In fact, it is only because
water is so a familiar substance that different names are used for __7

the solid, liquid and gas. Most substances are only familiar with __8

us in one state, because the temperatures requiring to turn them __9

into gases are very high, or the temperatures necessary to turn them
into solids are so low. Water is an exception in this respect, which
is another reason why its three states have given three different names. __10

答案

【答案】

1. 改like为as

describe sth as sth 是把……描述成……的意思。

2. 改heating为heated

在时间，条件，让步等状语从句中，当从句主语和主句主语是一致的时候，可以将从句的主语和be的变化形式省略。

3. 改with为of

be composed of 意思为“包括，由……组成”

4. 改is made up 为 are made up

which 指代上文中的 the gas， the liquid，and the solid，表示复数概念，所以要用are

5. 将第一个will去掉

在时间条件状语从句和条件状语从句中要用现在时表示将来时。

6. by改为when

when warm 相当于 when it is warmed

7. 改so为such

8. 改with为to

短语familiar to 后面才能接“某人” familiar with 是接sth

9. 改requiring为required

过去分词短语作后置定语时，和被修饰的名词时逻辑动宾关系。

10. have 后加 been

动词give和主语three states 是动宾关系