Is it legal to write something like this:

When I'm trying to post a form system alerts me with a warning message.

I've seen people use this kind of writing.


I don't know why (perhaps that's the influence of my native languages and their semantical constructions) but my brain is considering such a form

when I try to do something + present simple a.k.a something happens

I know that it would be just a description of usual activities like

each time I ...


My activity I want to describe holds repetitive character: I do some routine jobs but in the perspective of now, and this may not happen in the future.

Sorry if this sounds confusing.

  • The simple answer to this question as is stands is "yes, it's legal". It would be a much better question if you could expand on what makes you think it might not be. Sep 13, 2012 at 9:23

1 Answer 1


The combination of tenses is fine as it is. The bigger problem is its lack of punctuation, which leads to confusion.

The when clause is your adverb clause. Placed at the beginning of a sentence, normally it should be separated from the independent clause by a comma:

When S + V , S + V.

It's only when we place the adverb clause after the independent clause that we do away with the punctuation:

S + V when S + V.

Now there are two ways to cut up the meaning chunks of your sentence:

When I'm trying to post a form , system alerts me with a warning message.


When I'm trying to post , a form system alerts me with a warning message.

For me, the first is more likely to work than the second. But more importantly, what has caused this ambiguity is: (1) the lack of a comma, and (2) the lack of an article.

If it were me, I'd place a definite article in front of "system" :

When I'm trying to post a form, the system alerts me with a warning message.

The version without an article can work in a more casual style of writing.

  • You have answered a question you wish he had asked, not the one he did ask. Sep 13, 2012 at 9:37
  • 1
    Hi @RoaringFish. One, the title of the post is clear enough to me: "Mixed tense sentence." Two, RegDwight has already edited it. Three, the opportunity to teach the use of punctuation is too obvious to ignore. Four, I wish you'd place your downvotes according to the actual merit of the answer
    – Cool Elf
    Sep 13, 2012 at 9:41
  • Your answer (about punctuation) doesn't answer the question the OP asked (about tenses). As such it isn't actually an answer, hence has no actual merit as it fails as an answer, and hence deserves a downvote. Sep 13, 2012 at 9:45
  • 1
    This is not the first time someone in EL&U has corrected something else extremely vital to the validity of a sentence in question. In any case, the OP has already submitted his query, I have already submitted my answer, and I'll just wait and see how the others would judge it. Thanks for letting me know your personal reasons and I'd prefer not to extend this thread of comments
    – Cool Elf
    Sep 13, 2012 at 9:54
  • RegDwight's edit made no substantial changes (merely changing the style for the quote). The OP's edit was forty minutes after your answer, although I'm not sure it's actually clarified anything.
    – Andrew Leach
    Sep 13, 2012 at 10:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.