Hi,
You need to know how to use the verb "to be".
I am
you are
he/ she /it is
we are
they are
The 1st sentence (Shakespeare): to be or not to be, that is the question
(like in French : être oun epas être, telle est la question).
2. It is time for our Lesson. Be quiet !
The use of 'be' for "be quiet" is an order : c'est un impératif (soyez sages).
3. Just use what I wrote some lines before: I am, you are.
4. He is. Always. So here it is : Is he …? Yes he is / No he is not = no he isn't.
5. "that man" is exactly the same as "he" so now you know what to use !
He is => the man is , the boy is, Gaspard is, My brother is etc.