到过，英语的主从复合句一般分为三大类型: 名词性从句、形容词性从句和副词性从句。
名词性从句在整个复合句中起名词作用。主语、宾语、表语和同位语等各种从句统称为名词性从句，在句中起名词作用，充当主语、宾语、表语和同位语。
引导名词性从句的连接词可分为三类:
连接词: that, whether, if （不充当从句的任何成分）
连接代词: what, whatever, who, whoever, whom, whose, which
连接副词: when, where, how, why
主语从句是在复合句中充当主语的从句。
10.1.1 主语从句的引导词
主语从句通常由连词that和whether，连接代词或连接副词，以及关系代词what引导。
1) that引导
That each atom has a tiny but massive nucleus that contains protons and neutrons is a general phenomenon. 每个原子都有一个包含质子和中子的小而重的原子核，是个普遍现象。
That two objects carrying the same type of charge repel each other is certain. 带有同种电荷的两个物体互相排斥，这是确定无疑的。
That she became a physicist may have been due to her father's influence. 她成为物理学家可能是受她父亲的影响。
There seems little doubt that radar technology is a permanent and important aspect of research and development in electronics. (That引导的从句作实际主语）似乎没有疑问，在电子学的研究和发展中，雷达技术是一个永久并且重要的方面。
2) whether引导
Whether the experiment of dropping bodies of different weight from the leaning tower of Pisa was performed before a multitude, as some accounts have it, was not known.我们不知道比萨斜塔落体实验是否像某些资料记载那样在很多人目睹下进行。
Whether the plan of carrying out the experiment is feasible remains to be proved. 这一实验计划是否可行还有待证实。
Whether the discharge will do us harm remains to be seen. 放电是否有害还要看一看。
Whether the experimental result would support the theory was a problem. 实验结果是否会支持这个理论还是一个问题。
Whether a length is exactly a meter is a question no experiment can decide. 一段长度是否精确地是1m，没有实验能够决定。
3) 连接代词引导
Whoever discovered the phenomena did not make any difference. 到底是谁发现这个现象的，没有什么分别。
Whichever of the particles gets out first does not matter. 无论哪个粒子先出来都没有关系。
Who should be responsible for the environmental degradation is still unknown.谁对环境恶化负责还不清楚。
4) 连接副词引导
When mag
netism was recognized is not quite clear. 磁现象是什么时候被发现的，不是十分清楚。
How the experiment was done was a mystery. 这个实验怎样做的是一个谜。
How this happened