主语:是句子所要说明的人或事物，是句子的主体，主语的位置通常在句首，一般不省略，表示句子描述的是"谁"或"什么"，是谓语的陈述对象；通常由名词＼代词＼动词不定式＼动名词或从句担任．例如：1 [Walls] have ears.(名词做主语)2 [He] will take you to the hosipital.(代词做主语)3 [Three] plus four equals seven.(数词做主语)4 [To see] is to believe.(动词不定式做主语)5 [Smoking] is not allowed in public places.(动名词做主语)6 [The sick] were taken ca
