请帮我写一下5个主系表结构的词,要用第三人称单数做做主语,

题目

请帮我写一下5个主系表结构的词,要用第三人称单数做做主语,

答案

He is a boy.
He isn't a boy.
She is a girl.
She isn't a girl.
It is a dog.