The Present Perfect Tense

Use

In Portuguese there are several ways to refer to something that happened in the past, each with varying shades of meaning.  The present perfect tense includes expressions like these:

What have you been doing? > O que você tem feito?
I've been working all the time. > Tenho trabalhado tempo todo.
I've been calling you. > Tenho ligado para você.

Use it when talking about action that has been happening (and still is).

This is one of the most difficult tenses to get the hang of for several reasons. Everyone gets hung up on the fact that in Portuguese you don't (generally) use the verb to be to express been as we do in english. If you did it would be estado - and you actually can (and should) use it like this:

I've been tired lately > Tenho estado cansado esses dias.

This is fine, just a little formal sounding. Brazilians would say something more like, "Eu ando muito cansado esses dias".

The second reason this tense trips people up is that it's unlike other conjugations in that the form is TER + PAST PARTICIPLE.

Forming

ter (in the present) + past participle

-ar verbs

I have been working eu tenho trabalhado
he has been woring ele tem trabalhado
we have been working nós temos trabalhado
they have been working eles têm trabalhado

-er and -ir verbs

I have been watching eu tenho assistido
he has been watching ele tem assistido
we have been watching nós temos assistido
they have been watching eles têm assistido