Conjunctions are words that join phrases together. The most common in Portuguese are:

e - and
Os colegas bebem cafe frio e chá quente
The colleagues drink cold coffee and hot tea.
mas - but
Este copo está vazio, mas o outro copo está cheio.
This glass is empty, but the other glass is full.


porque - because
Eu tento interessar-me por política porque tenho que ir votar para o mês que vem.
I am trying to get interested (lit. interest myself) in politics because I have to go to vote next month.


enquanto - while
Ele cantou enquanto os seus pais ouviam.
He sang while his parents listened.


logo - therefore, so
''Estou cansado, logo não me vou levantar.
I am tired, therefore I won't get up.