7) 由or引导

The freezing temperature, or freezing point, is the temperature at which water freezes under ordinary pressure.结冰温度即冰点, 是水在常压下结冰时的温度。

StepⅢ Grammar 2: 同位语从句

1) 同位语从句

在复合句中用作同位语的从句称为同位语从句。同位语从句是名词性从句的一种。它在句中起同位语的作用。　

它一般放在fact, news, idea, truth, hope, problem, information, belief, thought, doubt, promise, question等名词的后面, 对前面的名词作进一步的解释, 说明前面名词的具体含义。引导同位语从句的词有连词that, 连接副词how, when, where, whether, what等。

e.g. The hope that he may recover is not gone yet.

The problem whether we should continue to do the experiment has been solved.

I have no idea when he will come back.

注意：同位语从句有时被别的词把它和名词隔开。

The story goes that William Tell killed the king with an arrow.

Word came that their team had won.

2) 同位语从句的表现形式:

① 由that引导

The fact that you don't have enough time to do the work is simply unbelievable.

The hope that he may come here is not gone yet.

The news that he has been elected president of the United States is true.

The truth that heavy objects and light objects fall at the same speed is known to all.

The problem that she later developed a serious lung disease bothered scientists.

② 由whether引导

The question whether we need more time to do the work has not been discussed.

③ 由when引导

I have no idea when they will go.

3) 有时可用namely (即), that is to say (也就是说), in other words (换句话说), that is(那就是), for example等引出同位语, 说明其前面的名词或代词。有时同位语直接跟在名词或代词的后面。

He told us the good news, namely, the museum is open to all.

There is only one way of improving your English, that is, to practice more.

Altogether Dolly had lived for six years, half the length of the life of the original sheep.

4) 同位语从句与定语从句的区别:

同位语从句与定语从句在使用中常常混淆, 我们可以从以下几个方面区别它们:

① 同位语从句说明的名词大都是抽象名词; 定语从句所修饰、限定的名词或代词有抽象的也有不抽象的。

② 同位语从句所说明的名词与从句没有逻辑关系；定语从句所限定的名词是