bus

In a sentence

• Vaig agafar el bus per anar a la ciutat.

  I took the bus to go to the city.

  Here, 'bus' is used to denote a means of transportation.

• El conductor del bus va ser molt amable.

  The bus driver was very kind.

  In this sentence, 'bus' is used to identify the particular vehicle being discussed.

• Estic esperant el bus a la parada.

  I am waiting for the bus at the stop.

  This usage of 'bus' is to indicate the specific public transport vehicle the speaker is waiting for.