Desde Há + Duration (EP Time Expression)
European Portuguese uses "desde há + time period" to express how long a situation has been ongoing up to the present. This is a characteristic EP construction.
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European Portuguese Grammar Guide
To express that an action has been going on for a period up to the present, EP uses desde há (or há… que) with the present tense. This is equivalent to English "for + duration" with a present perfect.
Vivo em Lisboa desde há cinco anos.
I have been living in Lisbon for five years.
Present tense in EP; the duration reaches up to now.
Há cinco anos que vivo em Lisboa.
I have been living in Lisbon for five years.
Alternative: há + duration + que + present tense.
🇵🇹 European Portuguese
Trabalho nesta empresa desde há dez anos.
🇧🇷 Brazilian Portuguese
Trabalho nesta empresa há dez anos.
BP omits "desde", using just "há + duration". In EP, "desde há" is the more characteristic form.
In EP, use the present tense with desde há or há…que for ongoing situations. Do not use the compound perfect (tenho trabalhado) for this duration-up-to-now meaning.
From a PortuStories Story
O senhor Ferreira trabalha naquela fábrica desde há quarenta anos.
Mr Ferreira has been working in that factory for forty years.