表语
表语是用来说明主语的身份、性质、品性、特征和状态的成分。
①That remains a puzzle to me.
②The sun is up.
插入语
在一个句子中间插入的一个成分,不作句子的何种成分,也不和句子的何种成分发生结构关系,同时既不起连接作用,也不表示语气,这样的成分是插入语。
①One advantage of his icebox, Moore explained, was something.
②The success of the Colorado beetle in infesting potatoes, for example, seems to be correlated with its high tolerance to alkaloids.
定语
定语是用来修饰、限定、说明名词或代词的品质与特征的成分。
①In science, a theory is a reasonable explanation of observed events.
②Possible solutions to the problem are formulated.
系动词
本身有词义,但不能单独用作谓语,后边必须跟表语,构成系表结构说明主语的状况、性质、特征等情况。
①That is air wrung dry of moisture.
②There seem to have been several periods within the last tens of thousands of years.
形式主语
形式主语it并无实际语义,只是为满足语法上的需要,避免句子头重脚轻,它代替的是句子的逻辑主语。
①It is no use reasoning with him.
②It was pretty hard for him to bring up the child on his own.
主语
主语是句子陈述的对象,说明是谁或什么,表示句子说的是"什么人"或"什么事"。
①My school is not far from my house.
②To do such a job needs more knowledge.