is是谓语吗
什么情况下is是谓语形容词？
is是谓语吗？
is有时候是系动词，有时候是助动词，做系动词用便是谓语形容词，做助动词用，并没有实意，不可以直接做谓语，要和主要形容词一起组成谓语。is做系动词的事例：The boy is clever，the girl is clever ,too. is做助动词的事例，The boy is doing his homework. The homework has been finished by the boy.
什么情况下is是谓语形容词？
is不论是系动词或是助动词，全是谓语形容词。
is既可作系动词用又可作助动词用。
词组：
1.He is a doctor.
is是系动词，是谓语形容词。后边跟表语，系动词is(be)和后边跟的表语一同组成谓语一部分。
2.Tom is playing the computer game.
is是组成现在进行时态的助动词，playing是现在分词，is和playing一同组成谓语一部分。
3.My homework is done every day.
is是组成被动语态的助动词，done是过去分词，is和done一同组成谓语一部分。
因此，is不论是系动词或是助动词，全是谓语形容词。
什么情况下is可单独作谓语？
主系表结构中，is单独作谓语。
He is from America.
She is nine years old.
Tony is a middle school stude.
My mother is a nurse.
My father is an engineer.
My grandfather is a lucky man.
之上语句都是is单独作谓语的事例。
下列句子中的is做为助动词，和后边的中文分词一起组成谓语。
He is learning English now.
the apple is eaten by my brother.