For - Since
English Grammar Rules
The use of FOR
We use For when we measure the duration – when we say how long something lasts.
For + a period of time
To measure a period of time up to the present, we use the present perfect tense and not the present tense.
- I have known her for a long time. (Correct)
I know her for a long time. (Incorrect)
- I have lived here for ten years. (Correct)
I live here for ten years. (Incorrect)
The present tense with For refers to a period of time that extends into the future.
- How long are you here for? (Until when)
- How long have you been here for? (Since when)
In reality, we can use all verb tenses with For.
|Uses of For|
|Example sentence||Verb Tense|
|They exercise for two hours every day.||Present tense|
|They are exercising for three hours today.||Present continuous|
|He has lived in Moscow for a long time.||Present perfect|
|He has been living in Turin for three months.||Present perfect continuous|
|I worked at the service station for five years.||Past tense|
|He will be in hospital for at least a week.||Future tense|
However, we don't use For with expressions such as all day or all the time.
- I was there all day. (Correct)
- I was there for all day. (Incorrect)
The use of SINCE
Since gives the starting point of actions, events or states. It refers to when things began.
Since + a point in time (in the past), until now.
- I've been waiting since 7 o'clock.
- I have known him since January.
With since we use the present perfect tense or the past perfect tense.
- I have been here since 5 o'clock and I am getting tired.
- I had been working since 5 o'clock and I was getting tired.
Since can also be used in the structure It has been + period of time + since.
- It has been two months since I last saw her.
- It has been three years since the last earthquake.
For vs. Since
Knowing when to use FOR and when to use SINCE is important. Therefore it is useful to look at a summary of the contrast between FOR and SINCE.
|FOR to mention a specific period (or duration) of time.||SINCE to mention the starting point of a period of time (continues to now).|
|I have been a doctor for fifteen years. (duration = 15 years)||I have been a doctor since 1992. (starting point = 1994)|
|She has been a mother for six months.||She has been pregnant since her first child was born.|
|My sister has lived in Frankfurt for nine months.||My sister has lived in Frankfurt since the beginning of March.|
Both For and Since are most commonly used with the perfect tense - we don't use these expressions in the present tense.
|I have learnt Russian for three years.||I learn Russian for three years.|
|They have taught geography since last year.||They teach geography since last year.|
|He has owned his dog since his cat died.||He owns his dog since his cat dies.|
While we can use For in the simple past tense we can't use Since in the simple past tense. Since can only be used in the perfect tense.
|She went to Japan for three years.||She went to Japan since 2003.|
|I studied in New Zealand for one month.||I studied in New Zealand since one month.|
|He walked his dog for four hours.||He walked his cat since four hours.|
It should be remembered that both For and Since have other meanings in English that are not associated with time.
- This is for you.
- Is this the train for London?
- Since you asked, I'll say yes.
- Since he didn't study he didn't pass the exam.
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