什么时候用助动词 什么时候用Be动词

如果句子中有实意动词的话,而你又要表达疑问或者否定的话,这是要用助动词.如果句子中没有实意动词,这时候要用be动词
例如; I like this book.
I don't like this book.
Do you like this book?
He is a great man.