Between the following couple of sentences, which one is right? Or better ask, which one is more right if both are right.

A: A keyword can not contain more than three words.
B: A keyword can contain no more than three words.

I'm an English learner, thus it ain't my mother tongue. So please feel free to teach me everything you think is needed. If there are any differences in meanings, mention it. If there is any preference to use each sentence (or other sentences you may suggest), tell my why.

  • A sounds much better to me. B sounds very awkward and possibly confusing. But I can't explain why, so hopefully someone can provide a better answer for you.
    – KumaAra
    Commented Sep 4, 2017 at 7:08
  • 3
    @KumaAra To me as a British native speaker B sounds more natural. I understood it immediately but had to think about A for a couple of seconds. Neither of them is incorrect but B is more usual in British English at least. I can't comment on American English. Having said that I would probably write it as "A key phrase must not contain more three words" because I find the.concept of one key word containing three words confusing and believe that the limit is defined rather than inherent.
    – BoldBen
    Commented Apr 2, 2018 at 11:57

1 Answer 1


Both are right. However, the first sentence is actually a bit ambiguous.

A keyword can not contain more than three words.

Does it imply that a keyword is NOT ABLE to contain more than 3 words? Or does it imply that SOME keywords MIGHT contain no more than 3 words?

To remove the ambiguity, replace "can not" with "cannot" (spelled together).

A keyword cannot contain more than three words.

Once you do that, there is no difference between the sentences in terms of meaning.

However, from a style perspective, if you are writing rules that human beings need to understand and possibly follow, the sooner they see the "no" word the better. Human attention tends to wander. So to make a stronger impression, go with option 1:

A keyword cannot contain more than three words.

If you want to lessen the perceived impact of a restriction, go with option 2.

A keyword can contain no more than three words.

  • Thanks for the explanation, what's the impact if we replace "Can" with "May"? Commented Sep 4, 2017 at 8:43
  • If "can" is replaced with "may", sentence B becomes ambiguous as well. "A keyword may contain no more than three words" might mean that more than 3 words are not allowed, or it could mean that less than 3 words are allowed. In general, "may" is usually used when describing a hypothetical state of affairs (something that may or may not happen) or something that a person is allowed to do if they want to ("you may leave early if you feel like it"). But in most cases people do understand that "may not" means that they're not allowed to do something. Commented Sep 4, 2017 at 21:52
  • Uh… no; not at all. Until you make a case for the amount of liquid in a half-empty or a half-full glass being different, … not contain more than… and … contain no more than… have exactly the same semantic value. They happen to argue one from a negative and the other from a positive perspective. Can and may change nothing except in very extreme cases of pin-dancing and even then, only debatably. Commented Sep 5, 2017 at 22:18
  • @RobbieGoodwin, what you say applies to "cannot". As I posted, there is no difference in that case. "Can not" is ambiguous because it can be interpreted as "[can not] contain" or as "can [not contain]". These 2 do not have the same semantic value. Another example is "Can you sleep? - I cannot sleep" as in I'm not able to sleep, vs "Can you please not sleep? - I can not sleep" as in I can stay awake. Commented Sep 5, 2017 at 22:39
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    I would argue that "can not" is not ambiguous, exactly because "cannot" also exists. "cannot" = impossible, "can not" = the negative is possible.
    – Flater
    Commented Nov 3, 2017 at 12:53

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