定义 ：构成句子的各个部分叫做句子成分。句子成分有主要成分和次要成分；主要成分：主语和谓语次要成分：表语、宾语、定语、状语、补足语、同位语I met my best friend Tom at the station yesterday .主语 谓语 定语 宾语 同位语 状语主语（subject）句子说明的人或事物 Jane is good at playing the piano.（名词）She went out in a hurry.（代词）Four plus four is eight.（数词）To see is to believe.（不定式）Smoking is bad for health.（动名词）The young should respect the old.（名词化的形容词）What he has said is true. （句子）找出下列句中的主语：1、The sun rises in the east. 2、Twenty years is
