Breakdown of O cientista está a trabalhar no laboratório.
estar
to be (temporary / location)
no
in the / on the / at the (m, f, pl forms: na, nos, nas)
trabalhar
to work
o cientista
the scientist
Questions & Answers about O cientista está a trabalhar no laboratório.
Why is it O cientista and not O cientisto?
Could I use trabalhando instead of a trabalhar here?
You could, but estar a followed by the infinitive (trabalhar) is the standard way to express ongoing actions in European Portuguese. Using the gerund (trabalhando) is much more common in Brazilian Portuguese or in specific regional dialects of Portugal.
Why use está instead of é for someone who is permanently a scientist?
Why does the sentence use no before laboratório?