在句子中起名词作用的句子叫名词性从句 (noun clauses)。名词性从句的功能相当于名词词组，它在复合句中能担任主语、宾语、表语、同位语、介词宾语等，因此根据它在句中不同的语法功能，名词性从句又可分别称为主语从句、宾语从句、表语从句、同位语从句、介词宾语从句等。
主语从句在复合句中用作主语的从句称为主语从句 (subject clause)。引导主语从句的关联词有从属连词、疑问代词、疑问副词、缩合连接代词、缩合连接副词等。如：
★ That they were in truth sisters was clear from the facial resemblance between them.
很明显，她们的确是亲姊妹，她们的脸型很相似。(关联词是从属连词that)★ Who should be responsible for the senior citizens has been widely discussed in our community.
谁应该对老年人负责这个问题在社区里被广泛讨论。(关联词是疑问代词who)★ Where we can dispose of the increasing rubbish is a great headache to many governments.
在哪儿处置日益增多的垃圾对很多政府而言是件头痛的事。(关联词是疑问副词where)★ Whoever pollutes the environment should be punished.
不论谁污染环境都应该受到惩罚。(关联词是缩合连接代词whoever)★ Wherever you are is my home—my only home.
你所在的任何地方就是我的家——我唯一的家。(关联词是缩合连接副词wherever)有时可以用it作为形式主语，将真实主语从句置于句末。如：
1. It is probable that the nocturnal trades go way back in the ancestry of all mammals.
很可能这种夜间的谋生可以追溯至所有哺乳动物的祖先。
2. It should be no surprise then that among mathematicians and architects， left-handers tend to be more common and there are more left-handed males than females.
在数学家和建筑学家中，左撇子更常见并且左撇子的男性比女性要多，这并不惊奇。
3. It is reported that millions of people die of water-related disease each year.
据报道每年有成千上百万人死于和水有关的疾病。
表语从句在复合句中用作表语的从句称为表语从句 (predictive clause)。引导表语从句的关联词有疑问代词、疑问副词、缩合连接代词、从属连词等。如：
★ The problem is who they can rely on.
问题是他们能依赖谁呢。(关联词是疑问代词who)★ The question is how they have achieved this.
问题是他们是怎样完成的。(关联词是疑问副词how)★ He looked just as he had looked ten years before.
他看起来还和十年前一样。(关联词是从属连词as)★ Indeed acting as a tourist is one of the defining characteristics of being ‘modern’ and the popular concept of tourism is that it is organized within particular places and occurs for regularized periods of time.
确实作为一个游客是“现代”的定义性特点之一，并且旅游的普遍性观念是它在某个特定地点组织并且发生于规律性的时间段。(关联词是从属连词that)宾语从句在复合句中用作宾语的从句称为宾语从句 (object clause)。引导宾语从句的关联词有从属连词、疑问代词、疑问副词、缩合连接代词、缩合连接副词等。如：
★ Animal right activists claim that animal tests are cruel， inhumane and unnecessary.
动物权益保护声称动物实验很残忍、没人道和不必要。(关联词是从属连词that)★ I know he has succeeded.
我知道他已经成功了。(在非正式文体中关联词that被省去)以上即是雅思阅读名词性从句的详细内容，大家在备考过程中可以将以上提到的几项实际引用到雅思阅读备考当中，以便更好的应对雅思考试。
雅思阅读考试对信息的定位考查很严格，理解掌握能力要求很高，所以为了能够准确定位，一定要理解文章的句型结构，这样才能更加对考生有所帮助.
