Since, for and ago: talking about periods of time

by Liz Walter
since for ago
It often seems that small, common words cause the most mistakes, and I certainly hear my students making errors with words like since, for and ago. This post therefore looks at some common errors connected with talking about periods of time and explains how to avoid them.

First, let’s look at the difference between since and for. They are both used to say how long something has been happening, but while since is followed by a precise time or a date, for is followed by a length of time:

She has lived here since 2011.

I’ve been waiting since 10 o’clock.

She has lived here for 3 years.

I’ve been waiting for over an hour.

He’s been a teacher since twenty years.

It is also common to follow since with a phrase that describes a specific time:

I’ve been playing the piano since I was five.

It’s the hottest summer since records began.

Note that when you talk about how long something has continued up to the present time or the time you are talking about, you need to use a perfect form of the verb:

I’ve known her since 1995.

I know her since 1995.

I knew her since 1995.

If you want to ask someone questions about the length of time something has existed or been happening, the most common way is to use How long …? with a perfect tense:

How long have you lived here?

How long had they known about the document?

Unlike for, since can also be used as an adverb, usually at the end of a sentence.

I met him at Jake’s party, but I haven’t seen him since.

To emphasize that a situation hasn’t changed over a period of time, we often say ever since:

She came to visit us in May, and she’s been here ever since.

He’s been grumpy ever since he arrived.

The word ago is used to say how long before the present something happened. It always comes at the end of the sentence or clause:

She called me about an hour ago.

Dinosaurs lived millions of years ago.

To talk about a period of time from its beginning to its end, we use from … to

He worked for the company from 2011 to 2014.

The course runs from May to July.

So if you’ve been struggling with these words for a long time, perhaps since you started learning Engish, which could be many years ago, I hope they will be clearer now!

 

11 thoughts on “Since, for and ago: talking about periods of time

  1. Konstantin

    Thank you for your explanation!It always is interesting to learn some details concerning grammar.However,there is a sentence as the follows:
    ‘She had lived alone ever since her husband died.’
    I can not agree with the structure of this sentence.My understanding is that the sentence should be built like this:
    ‘She had lived alone ever since her husband had died.’Otherwise,tense egreement rules are not followed.Could you clarify this point,please?

    1. Liz Walter

      Hi Konstantin. I’m not sure where you read that sentence, but it is fine, though yours is possible too. In the first, the writer is probably thinking of the death as a one-off occurrence in the past. In the second, there is more emphasis on the fact that this happened at a time before the narration began. Past perfect sounds a little clumsy, so we tend to use it only when it is really needed and to try to avoid using it too many times in one sentence.

  2. Jorge D

    Very good explanation. Thank you very much. Quick question: Could we also use “from… through” instead of “from… to” to talk about a period of time from its beginning to its end?

    1. Liz Walter

      No, I’m afraid not. We don’t usually use since or for with ago – just use one of them in the sentence. I think what you want to say it: I have been working there for 3 years. (You can also say: I started working there 3 years ago. Or: I’ve been working there since 20014.

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