一、英语句子成分和英语句子结构讲解：（一）句子成分1.主语（subject）: 句子说明的人或事物。 主语可以由名词、代词、数词、不定式、动名词、分词、主语从句和短语等来担任。 The sun rises in the east.（名词） He likes dancing. （代词） Twenty years is a short time in history. (数词) Seeing is believing. （动名词） To see is to believe. （不定式） What he needs is a book. （主语从句） It is very clear that the elephant is round and tall like a tree. （It形式主语，主语从句是真正主语）找出下列句中的主语：Jane is good at playing the piano.（名词） She went out in a hurry.（代词）Four
