Sambhram instituti

Present participle 

What if you want to use to be as the main verb in a continuous tense? In this case, you would use to be twice: first as an auxiliary verb and second as a present participle. 
Don’t listen to me: I am being paranoid. 
This works for the present and past continuous tenses, but we generally avoid using to be as the main verb in the future continuous—the simple future works fine in this situation. 
[INCORRECT] I will be being hungry tomorrow. 
[CORRECT] I will be hungry tomorrow. 

Past participle 

The perfect tenses use a conjugated form of the auxiliary verb have with the past participle of the main verb afterward. 
[conjugated have] + [past participle]
The past participle of to be is been, used if to be is the main verb in a perfect tense. The present perfect tense uses have or has, while the past perfect uses had:
I have been tired since my first day of school. 
It had been a bad day even before it started raining. 

To be grammar rules

1.Subject-verb agreement

All verbs must agree with their subjects, something called subject-verb agreement. This means that the verb’s person and number must match the subject’s. So if the subject is first person and singular (I), the verb must be first person and singular (am). 
[INCORRECT] Felipe am class president. 
[INCORRECT] Felipe are class president. 
[CORRECT] Felipe is class president. 
Most regular verbs change only for third-person singular subjects in the present tense, but to be is more complicated because it has more forms than other verbs. 
One particularly difficult area of subject-verb agreement concerns when to use there is vs. there are which we cover in detail here. To summarize, when it follows there, the verb to be matches the number of the noun after it and not that of the subject. 
[INCORRECT] There is the ducks. 
[CORRECT] There are the ducks.