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Hi all!

The population of the town has grown from a few hundred to 10,000 in little more than a decade.

The population of the town has grown from a few hundred to 10,000 for little more than a decade.

Clearly the second one is wrong, but why is for is not an acceptable substitute for in in this sentence when in refers to the period of time over which the event has taken place and for is used for duration in other sentences, such as I've been collecting them for about 10 years or I had a nap for a few minutes?

The population of the town has grown from a few hundred to 10,000 over little more than a decade.

Why does it have to be in over or over the course of and not just over?

Thanks.
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Ditch
The population of the town has grown from a few hundred to 10,000 in little more than a decade.

The population of the town has grown from a few hundred to 10,000 for little more than a decade.

Clearly the second one is wrong, but why is for is not an acceptable substitute for in in this sentence when in refers to the period of time over which the event has taken place and for is used for duration in other sentences, such as I've been collecting them for about 10 years or I had a nap for a few minutes?


I think "for" implies that the thing is happening continuously (or continually) over the stated period; for example: "I've been collecting butterflies for ten years", "The population of the town has been growing for ten years." At any given point in those ten years, the population was growing, so my second example sentence is OK. However, in your population example the thing being described took the whole ten years to happen, rather than happening continuously throughout the ten years, if you see what I mean. Therefore "for" does not work.

A similar example where the same principle seems to apply: "I worked hard for ten years", yet "I worked my way from office boy to director in ten years."
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Ditchwhy is for is not an acceptable substitute for in
It is not acceptable because the sentence mentions the end point of the growth (10,000).

You can go from point A to point B in an hour, but you can't go from point A to point B for an hour. In other words, it takes you an hour to go from A to B; it's not that you spend an hour to keep going from A to B.

When you mention the end point you're saying that the process has finished. You can say that you finished (something) in a week, but not that you finished it for a week. So any time the concept of finishing is somehow involved, you need in, not for. You can't have finished an action (in) and still be doing it (for) at the same time.
DitchI've been collecting them for about 10 years
Another example. You can't say you collected them until you had 100 of them for 10 years. You collected 100 of them in 10 years. You didn't collect 100 of them for 10 years. But you can say you've been collecting them for 10 years because that implies that you are still collecting them. No end point is mentioned.
DitchThe population of the town has grown from a few hundred to 10,000 over little more than a decade.

Why does it have to be in over or over the course of and not just over?
In my opinion, just over is not that bad, but again, the in is an acknowledgment of the fact that you've reached the end point. Adding the course of gives the same effect as in.

Regardless, over is ambiguous with amounts. over a decade can mean more than a decade. That makes over (used alone) too confusing in this sentence.

CJ
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That sounds right.

Thanks very much. Emotion: smile
 CalifJim's reply was promoted to an answer.
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Mr WordyI worked my way from office boy to director in ten years.
"director" is the end point. My method works!

Emotion: smile

CJ
Thanks! That answered my questions perfectly. Emotion: smile