THEN for three months >N0W
since my birthday
THEN from six o’clock NOW
from now on
three years ago_
three years before THEN
For details of the use of ago and before
- [ for + period of time]
I once studied the guitar for three years.
That house has been empty for six weeks We go away for three weeks every summer.
My boss will be in Italy for the next ten days.
When we talk about a period of time up to the present, we use for with the present perfect tense (have + past participle).
I’ve known her for a long time. (NOT Iknow-her . . .)
A present progressive with for often refers to the future.
How long are you staying for? ( = Until when . . .)
We can leave out for with How long . . .?
How long are you staying ?
How long have you been waiting?
from/since + starting point
I’ll be here from three o’clock onwards.
I work from nine to five.
From now on, I’m going to go running every day. From his earliest childhood he loved music.
I’ve been waiting since ten o’clock.
I’ve known her since January.
Since gives the starting point of actions and states that continue up to the present; from gives the starting point of other actions and states.
THEFT from nine to five >TH£N
THEtf from his childhood
from three o’clock onwards NOW from now on
since ten o’clock
For and since can both be used with the present perfect (have + past participle). They are not the same.
- [ for + period] [ since + starting point]
I’ve known her for three days. I’ve known her since Tuesday.
I ‘ve been here for a month. I ‘ve been here since July.
I’ve had my car for ages. I’ve had my car since 1980.