I would like to know whether I get it right:

The siblings lived with abusive parents. They could run away anytime if they wanted.

Would this be correct if I mean this as their ability over the years? Or "could have run away" is required to?

I ask as I have seen the following sentences:

He could start a business in the nineties.
EDIT: Fixed a typo

Which native speakers told me it is correct as it refers to a longer period and thus ability or possibility that he had.


The decision between "could have" and "could" really isn't about whether an action is a single occurrence or repeated. It just depends on your intended meaning.

"Could" in this kind of situation really has 2 possible meanings, similar, but sometimes subtly different.

#1 past tense of "can" [E.g. "He gave what he could give."] This "could" tells about someone's ability/capability in the past.

#2 expressing a shade of doubt or a lesser degree of ability or possibility [E.g. "It could be so."] This one is for speculating about the likelihood of an event happening (or not).

It is rather confusing that the past tense of sense #1 looks just like the present tense of sense #2.

#1 [can/could; someone's ability]

present: "He can swim." [He has that ability]

past: "He could swim." [He had the ability at that time]

#2 [speculating about something happening.]

present: "What should I do on such a beautiful day? I could swim out to the island and get some exercise." [I might do that]

past: "Where did Arthur go? He could have swum out to the island for some exercise." [Maybe he did.]

So addressing your examples:

1) He could start a business in the nineties.

2) He could have started a business in the nineties.

Either of those can be right grammatically, depending on what you mean to say. The first one is about what he was able to do. It says that in the nineties he was capable of starting a business. (And perhaps he did.) The second one speculates about what might have happened in the nineties (He might have started a business. But since the discussion remains hypothetical, even though the nineties are over, the implication is that it didn't happen.)

Your original example is similar except for some extra context.

The siblings lived with abusive parents. They could run away anytime if they wanted.

That last sentence tells us they could run away if they wanted. Since it speaks of an event in the past which remains an 'if', we would probably assume that they didn't do it (because they didn't want to).

So I feel that the statement should be interpreted as in sense #2. In other words it is about a past event that might have happened (but it didn't). So the verb should be "could have run".

The siblings lived with abusive parents. They could have run away any time if they wanted.

The other interpretation could also be valid, if you just want to state that they had the ability to run away whenever they wanted. In that case my preference would be to lose the "if":

The siblings lived with abusive parents. They could run away anytime they wanted.

But the whole statement sounds less likely that second way, and I don't think that is the intended meaning.

Note that the two uses of "could" are closely related. Many situations are about both someone's ability/capacity and speculation about something happening. So it often doesn't make a bit of difference which sense you choose for your statement.

In cases where it does matter, people fluent in English will know without thinking which "could" they mean, and they will select the verb tense accordingly. But if you ask us to say why, then we try to figure it out, and we get so confused, we often come up with bogus reasons, such as: "It's because it's a single event vs. a longer time period."; "We don't use 'could' in a positive sentence when referring to a single occasion."; "You only say 'he could have' if he didn't."; or "The words just flow better that way."

Some of those explantions could be valid in specific examples, but the real reason (in general) is this: If you are talking about the past, "Could" is for someone's ability or capacity, and "could have" is for discussion about something maybe happening (or not).

Formal definitions for "could" used in sense #1 and sense #2 are given by https://www.yourdictionary.com/could as definitions 1. and 2.a. respectively.

  • Gosh, the "He could started" was a typo, thanks! Just to add - what if I change the sentence and instead of "the nineties" place e.g. 1992? I think then I cannot use "could" anymore as it is more like a single occassion? – John V Feb 19 at 16:31
  • 1) He could start a business in 1992. vs. 2) He could have started a business in 1992. Either sentence is still fine. The difference in meaning isn't about single events vs. repeated events. It is about "he could do it" regarding the existence of a past capability vs. "he could have done it" about something he might have been able to do (but probably didn't). The fact that we are still speaking only about the possibility of an event (or events) clearly marked as belonging to the past strongly suggests that the event(s) didn't happen. – Lorel C. Feb 19 at 16:43
  • Thank you, then I am still confused - "I could start a business in 1999" was by another native speaker considered incorrect, with the explanation: The problem here is that we don't use 'could' in a positive sentence when referring to a single occasion. So here I'd use 'I was able to start a business in 1999'. Could + verb referring to the past is for 'general ability in the past' (as opposed to ability on one occasion, so – John V Feb 19 at 17:20
  • what I mean is that e.g. "I could start a business yesterday" or "I could visit you yesterday" sounds off to many native speakers, with arguments that the capability is long-term, is not something that that you can do just a day, you either "can" do it or you "cannot". (Stating what I was told) – John V Feb 19 at 17:24
  • I think your native speaker is making reasonable assumptions abt the possible intended meaning based on what is likely & common. Why would a person ever want to say, "I could visit you yesterday."? Probably you just called him today, but yesterday he could have visited, so he should use "could have". But here is a more unusual situation: Your mom complains because you won't visit today, but yesterday you offered to visit. "Why can't you come today if you could come yesterday?" "I could visit you yesterday because I had the car. Today Susie took it to work." Unlikely situation, but OK English. – Lorel C. Feb 19 at 17:40

"could have run away" fits better. Otherwise, it is OK.

Personally, I use use (in this case) "at any time" instead of "anytime", but I cannot explain why - maybe it just flows better.

So the end result is:

The siblings lived with abusive parents. They could have run away at any time if they wanted to.

A different context would be:

The door was open. They could run away if they wanted.

The context is different if you look at the duration of the actions:

  • "lived with parents" - a very long time, most likely years;
  • "was open" - very short action (at least when compared with "lived with parents").

He could started a business in nineties.

should actually be:

He could have started a business in the nineties.


He could start a business in the nineties.

depending on the intended meaning.

  • So why the very last sentence works simply with "could" (He could start a business in the nineties) but not the one with siblings? – John V Feb 19 at 9:27
  • Because "He could start a business" is not provided in a context :) – virolino Feb 19 at 9:28
  • Could you then please explain in the answer with a context for both variants? Could the sentence "They could run away if they wanted" also work in another context? – John V Feb 19 at 9:30
  • I did my best. I am no longer deeply familiar with all the details of the grammar, to explain tenses, correlations... In every-day life, I use English without care as to why it is correct - pretty much like any person speaking their own native language. Maybe another friend here will jump in. – virolino Feb 19 at 10:07
  • Thanks, although it got me confused even more :D "could" is said to be used only with long-term abilities, while "could have" for past possibilities. In your example, it is exactly the other way around :) – John V Feb 19 at 10:09

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