formation of sentences and usage of since,for and from

Is the sentence "have not heard from u for long." correct?Plz give me the correct sentence formations using "since","for","from".I'm always confused abt their usage.

[Casiopea]

Originally Posted by kcshalini

Is the sentence "have not heard from you for long." correct? Please give me the correct sentence formations using "since","for","from". I'm always confused abt their usage.

I have not heard from you for a long time.
I have not heard form you since Monday.

Use 'for' with periods of time, and use 'since' with specific points in time, like this,

More than one day, hour, minute, month, second, year, etc
for a week
for a day
for 2 months
for 5 minutes

One day, time
since Monday
since yesterday
since 4 o'clock
since I last saw you
since the last time I saw you

All the best, :D