句子成分
主语(subject): 句子说明的人或事物。
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)
谓语(predicate): 说明主语的动作、状态和特征。
we study english. he is asleep.
表语(predicative): 系动词之后的成分,表示主语的性质、状态和特征。
he is a teacher. (名词) &n