Difference between "for" and "since"

BABA   Wednesday, June 18, 2003, 19:23 GMT

We often make mistakes about these words: "for" and "since". What is the difference between "for" and "since"?

For example: I have been playing tennis since I was 7 years old.
She had been waiting for 20 minutes when paul arrived.

What do you think?

Nice to read your comments.
hp20   Wednesday, June 18, 2003, 21:25 GMT
i don't know if i'll explain this well, but here goes.

"since" is used in reference to the beginning of a time period.
"for" is used to describe the length of time.

for example, it's 2:30 in the afternoon and you've been waiting for the bus. the bus was supposed to arrive at 2 o'clock. if you wanted to express the length of time you've been waiting, you'd say "i've been waiting here FOR 3 minutes." if you wanted to tell someone when you started to wait, you'd say "i've been waiting SINCE 2."

so basically "for" refers to length of time and "since" refers to when the activity began.
Tom   Wednesday, June 18, 2003, 21:33 GMT
What about:

"I've been spending 3 times more on gasoline since I've had this car."?

Doesn't "since" refer to a length of time here (the period in which the speaker has had the car)?

As usual, I think the best way to learn English grammar is not to look for rules and explanations, but to study example sentences instead.
efmvamn   Wednesday, June 18, 2003, 21:37 GMT
Why, it's important to help you with rules and explication at the begining. Then you'll get a more precise idea of the spirit of a word by studying examples.
Fisher   Wednesday, June 18, 2003, 23:04 GMT
What about "for" and "since", where they mean "because"? Is there a difference in such cases?
Jacob   Wednesday, June 18, 2003, 23:57 GMT
When `for' and `since' are used in time expressions, `for' is joined with a measurement of time: for 20 minutes, for 5 years, etc. `Since' is joined with an event that indicated the beginning of the period: Since I was born, since yesterday, since the first time we met, since I got this car.

In Tom's example, there's no measurement of time, but there's an event marking the beginning of the time period. That's why `since' goes there. For what it's worth, it would be legitimate, and equivalent, to say, "I've been spending 3 times as much on gasoline since I got this car."
Jim   Thursday, June 19, 2003, 00:13 GMT
I've got to agree with Tom that the best way to learn is to study example sentences. This is particularly true for the question Fisher asked. However, as a basic rule of thumb what Jacob & hp20 wrote is a good guide-line but remember: rules are there to be broken.
Jacob   Thursday, June 19, 2003, 00:19 GMT
I think the distinction between `for' and `since' is a fairly rigid one for the English language. If there are good examples that diverge from my explanation, I'd be interested in seeing some.
Jacob   Thursday, June 19, 2003, 00:22 GMT
That said, I'll echo everyone else in saying that deductive (as opposed to inductive) reasoning is the way to go. Look at lots and lots of good examples and you'll get a feel for the usage which is much better than trying to remember a rule and apply it to each new situation.
Lana   Thursday, June 19, 2003, 02:02 GMT
Well, I think it is very important to understand the underlying rule -- at least for me and the way I learn. Of course, it is also necessary to study many examples and practice speaking a lot.

I think studying the rule provides an important basis for understanding during the learning process. Practicing many examples provides the repetition that allows you to develop the feeling that a sentence "sounds right" or "sounds wrong." At that point you can forget about the rules.

An analogy is learning to play the piano by reading sheet music. Learning the notes and harmonious keys, chords, etc.
Then after practicing a lot, you can throw away the printed music and play the songs you have learned, as well as improvise your own music.
Jim   Thursday, June 19, 2003, 02:59 GMT

What do you mean by deductive and inductive reasoning?

It seems to me that looking at lots and lots of good examples and getting a feel for the usage is more like inductive reasoning. While trying to remember a rule and applying it to each new situation is more like deductive reasoning.


I agree with you that you should keep practising. They say "Practice makes perfect." However, if you ask Tom, he might tell you not to practise until you're already perfect. I don't agree with him 100% but he has a very good point. If you practise bad examples, they become reinforced in your head and harder to shed.
Lana   Thursday, June 19, 2003, 03:27 GMT
That's why I say that it is important to understand the rules--then you know by the rule if the example is correct. Until you have practiced enough to get the intuitive feel - you must use the rules to know that you are using correct sentences. Otherwise you wouldn't realize if you are using bad examples.
chantal   Thursday, June 19, 2003, 04:42 GMT
'For' indicates a length of time : "I've been reading for two hours now". "He's been living in Boston for ten years now".

'Since' (used with the present or past perfect tense) indicates a length of time from a specified time in the past until a later past time or until now :
"He's been sick since Monday", "I haven't seen him since last week".

'Since' (used with the present perfect, past perfect or simple present tense in the main clause) indicates a lenght of time from a specified event in the past until a later past event, or until now :
"Tim hasn't phoned since he went to Paris", "How long is it since we last went to the cinema ?", "It was the first time I'd had visitors since I'd moved into the flat".

As a learner, I agree with Tom's point of view about learning lots of good examples from scratch.
Personally, I learnt the use of "since" and "for" by examples. I learnt rules little by little, but at the beginning I was unable to explain why we should say : "I've been learning English for three years" or "I've been living in London since 1985".
Jacob   Thursday, June 19, 2003, 10:26 GMT
Jim, you're exactly right, I mixed up deduction and induction.
Tom   Thursday, June 19, 2003, 12:27 GMT

You said "In Tom's example, there's no measurement of time, but there's an event marking the beginning of the time period."

The sentence was:

"I've been spending 3 times more on gasoline since I've had this car."?

There is no event in this sentence. The sentence is about having the car -- having something is not a point in time. It's a period of time.

If the second part of the sentence read "since I got this car", then I would agree with you. Getting something is a point in time.

My point, of course, is that it is not entirely correct to say that "since" is used with events and "for" with lengths of time. "Since" can be used with lengths of time as well.

An even bigger point is that grammar rules are merely awkward approximations of the real way a language is used. To me, this is yet another reason to study example sentences instead of memorizing rules.

The main reason is that the brain is much better at imitating examples (generalizing them) than it is at applying abstract rules. This is evident in many areas. For example, it is a lot easier to learn to drive a car by looking at someone do it than by reading about it. The same goes for learning to solve quadratic equations, etc.