1. 
The verb to be is used as the main verb
tense to state that something or someone
exists.
AFFIRMATIVE SENTENCES
NEGATIVE SENTENCES
QUESTIONS AND SHORT/LONG
ANSWERS

2. AFFIRMATIVE SENTENCES
SUBJECT
VERB
TO-BE  COMPLEMENT
http://www.eclecticenglish.com/grammar/PresentSimpleToBe1A.html

3. NEGATIVE SENTENCES
SUBJECT
VERB
TO-BE
 NOT COMPLEMENT
I AM NOT PAUL
HE, SHE IS NOT A STUDENT
IT IS NOT A CAT
WE, YOU, THEY ARE NOT IN THE HOSPITAL
http://www.mansioningles.com/gram37.htm

4. SHORT/LONG ANSWERS
IS HE, SHE

A STUDENT?
YES, HE/SHE
YES, HE/SHE IS A STUDENT?
NO, HE/SHE IS NOT
NO, HE/SHE IS NOT A STUDENT
ARE THEY IN THE HOSPITAL?
YES, THEY ARE
YES, THEY ARE IN THE HOSPITAL
NO, THEY AREN NOT
NO, THEY ARE NOT IN THE HOSPITAL
http://www.englisch-hilfen.de/en/grammar/frage1.htm

5. 