"He tries to improve his English."
Translation:Ele tenta melhorar o seu inglês.
what is the rule when to say the "a" before of the infinitive and when not say it as here: "ele tenta melhorar" or "ele quer melhorar"
some verbs require preposition, others dont. The only way to get them is by learning the prepositions that go after them. Tentar, for instance, does not require the preposition A
Prepositions meanings vary a lot. In this case, the verb is há and it does not need preposition.
So "Há muito". The sentence could end here, but there is an additional information, and that "a" preposition is a "finality" preposition adding information to "muito".
muito a fazer = Lot to do, or to be done.
so the "a" is here because of the "muito" not "considerar", for example if the sentence starts quero... it would be quero considerar and not quero a considerar? am i right?
Half of it is right. It's not considerar that demands preposition.
This is right: Precisamos considerar. (we need to consider)
This too: Temos muito a fazer. (we have a lot to do)
But it's not a rule that "a" must be used after muito. It's used in the expression "ter muito a + infinitive", meaning "to have a lot to + verb"
Why: Ele tenta melhorar "o" seu inglés? Why wouldn't "Ele tenta melhorar seu inglés" be correct?