The basic principle of verbal agreement, of course you know, is demarcated by the fact that the verb agrees with the subject in person (I, you, he...) and number (singular or plural). If you no longer remember this subject, how about accessing the textVerbal agreement?
However, there are some verbs that have some peculiarities that often escape this basic criterion, so to speak, as is the case of the verb to exist and also to the verb to be. Thus, as these are some rules that we should be aware of, it is always good to pay attention to all of them, especially at the moment we are writing, because as you know, the written modality requires competence, above all.
Let's see how the agreement of the verb to be occurs:
* When the subject or the predicative it's a person's name, the agreement is with the person.
Beatrice it was the family's concerns.
* The verb to be agrees with the personal pronoun, acting this (the pronoun) in the subject or predicative quality:
Brazil is us.
They were the College.
* In case the subject and the predicative are names referring to the thing, as well as having different numbers, the verb to be preferably agrees with what is in the plural.
Your attitudes are the secret of good coexistence.
* In the case of expressions that indicate quantities, such as measure, weight, value, etc., the verb to be remains unchanged.
Ten thousand is too little.
Five kilometers is enough.
Twenty pounds is too much.
* The verb to be, in the indication of hours and distance, may agree with the predicative.
It's one o'clock.
It's two kilometers.
