学习好资料欢迎下载（一）句子成分的定义：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；主要成分有主语和谓语；次要成分有 表语、宾语、定语、状语、补足语和同位语。（一）主语 (Subject) 主语是一个句子所叙述的主体，一般位于句首。（但在 there be结构、疑问句（当主语不疑问词时）和倒装句中，主语位于谓语、助动词或情态动词后面。）主语可由名词、代词、数词、不定式、动名词、和主语从句等表示。例如：1.Three plus two is five. 2.It is a great pleasure to swim in the river 3.Smoking does harm to the health. 4.There are many students in my class. 5.Are you a student? 6.Here comes the bus. 7.He can do it and so can I . 8.Who will attend the meeting has not beendecided. （主语从句）学习好资料欢迎下载（二）谓语(Predicate) 谓语说明主语所做的动作或具有的特征和状态。动词在句中作谓语，一般放在主语之后。谓语的构成如下：1、简单谓语：由一个动词或动词短语构成。如：He practices running every morning. The plane took off at ten o’clock.2、复合谓语：（1）由情态动词或其他助动词加动词原形构成。如：You may keep the book for two weeks. He has caught a bad cold. （2）由系动词加表语构成。如：We are students. He practices running every morning. The plane took off at ten o’clock.（三）表语 (Predicative) 表语用以说明主语的性质、 特征、状态与身份，它一般位于系动词 （如be, become, get, look, grow, turn, seem等）之后。表语一般由名词、代词、形容词、数词、副词、不定式、动词ing、介词短语及表语从句表示。例如：1.The weather has turned cold. 2. The speech is exciting. 学习好资料欢迎下载3.His job is to teach English. 4. The meeting is of great importance. 5. Time is up. The class is over. 6. The truth is that he has never been abroad. （四）宾语（ Object）宾语表示动作的对象或承受者， 一般位于及物动词和介词后面。 例如：1.They went to see an exhibition yesterday.（名词）2.The heavy rain prevented me from coming to school on time.（代词、...
