For X Since – Quando usar cada um

For

Use FOR if you don’t have to calculate the period of time, because you have it in the sentence:

I have lived here FOR two months (you don’t have to calculate, you know the period is “two months”)

Since

Use SINCE if you have to calculate the period of time, because you only have the starting point:

I have lived here SINCE 1975 (you have to calculate now: if you came in 1975 – the starting point – and now it is 2009, then 2009-1975 = 24 years)

Ajude-nos a compartilhar o conhecimento
por toda interweb!

É só um clique! =)