Verb To be

     The Verb to be is one of the most important verbs in English language, at the same time is one of the most complicated verbs.

     You can use it as a Verb and you can use it as an auxiliary verb too.

Verb To be has different Forms, as you can see in the chart. 

• Positive (+) = the positive form is the easiest form of the verb it is composed just for a Subject, Verb and a complement. 

Ex:  I am a positive person

      She is smart 

      The cat is in the door

• Negative (-)=The negation of the verb to be is formed by placing not after the inflected form of this verb

Ex:  I am not hungry

       She is not beautiful

       You are not a bad person

• Question (?) = The verb to be is used to create simple yes/no questions by simply inverting the order of subject and the “To be” verb.

Ex: Am I right?

     Is she late? 

     Are you fine?

How and When we can use the contracted form of the verb?

Many students have those doubts, and we are here to resolve it. 
You can use Contracted form in colloquial situations, technically speaking, contractions aren't necessary in written English. Using the full version of a word is always grammatically correct. However, there are a number of reasons why contractions do serve a valuable stylistic purpose.

See you soon,  C.