Breakdown of Porque é que a porta está trancada?
ser
to be
estar
to be (temporary / location)
a porta
the door
porque
because
Questions & Answers about Porque é que a porta está trancada?
Why does trancada end in an -a here?
Trancada is the past participle of the verb trancar (to lock). Because it is used here with the verb estar to describe the resulting state of the door, it acts just like an adjective. Since a porta is feminine and singular, the default -ado ending changes to -ada to match it.
Why use está instead of é for this sentence?
We use está (from estar) because being locked is a temporary state or the result of an action. If you used é (from ser), it would sound like a passive voice action, like saying 'The door is locked by someone every day', rather than describing its current physical condition.
What is the purpose of é que after Porque?
Porque é que literally translates to 'Why is it that'. In Portuguese, it is very common to add é que after question words to make the question sound more natural and conversational. A handy bonus of using é que is that you do not have to flip the subject and verb: you can just say a porta está in normal order instead of está a porta.
What is the difference between trancada and fechada?