Para is used with expressions denoting quantities:Es demasiado fuerte para mí.
It’s too strong for me.Basta para satisfacer al jefe.
That’s enough to satisfy the boss.25.1.22.3 Parain time expressions
Hazlo para el lunes que viene.
Do it by next Monday.Mi novia ha ido a España para una semana.
My girlfriend has gone to Spain for a week. (= in order to spend a week
there)25.1.23 Por25.1.23.1 Pordenoting cause or motive
¿Por qué te levantaste tan temprano?
Why did you get up so early?Por la lluvia no pudimos venir. (see 43.2)
Because of the rain we could not come.Por razones personales no pudieron asistir. (see 43.3)
For personal reasons they were not able to attend.Por no tener dinero sólo comíamos pan.
Because we didn’t have money we ate only bread.Hazlo por tu madre.
Do it for your mother’s sake.Luchamos por la libertad.
We are fighting for the sake of freedom.25.1.23.2 Pordenoting substitution
Cambié el coche por una bicicleta.
I changed the car for a bicycle.El ministro firmó por el presidente.
The minister signed on behalf of the president.25.1.23.3 Pordenoting movement through or time during
Pasamos por el centro de la ciudad.
We passed through the city centre.Madrid por la N-VI.
Madrid by way of the N-VI (road).Basic use of prepositions 25.1