What is an important piece of information missing from this recipe

What is the recipe? copy and paste it into the comments and i will answer it for u!

1a) We've Been here FOR an hour.
1b) We've been here SINCE 4 o' clock. 
2a)She hasn't spoken to me FOR 2 weeks.
2b) She hasn't spoken to me SINCE last week.
3a) They've live in this street SINCE 1970.
3b) They've lived in this street FOR a long time.
4a)I haven't had time to do it SINCE last Monday.
4b) I haven;t had time to do it FOR a few days.
5a) We haven't bought a new on SINCE ages.
5b) We haven't bought a new one FOR many years.