For as long as I can remember, I distinguish past tense from perfect tense from the intention of the sentence. If the sentence intends to emphasise on the time, then it's past tense. If the sentence intends to emphasise on the "finish-ment" of something, then perfect tense it is. And past perfect is just the finish-ment of something at time point of reference in the past.

And then I use the rule of thumb that everything with "just" usually is having "perfect" tense somewhere in the sentence, whether it's perfect tense, past perfect tense, or future perfect tense.

My wife had just posted a picture in her instagram saying that:

"Having this phone for a year, yet I just knew my phone camera has automatic flash feature."

I corrected her that she should use "yet I have just known" instead of "just knew" because I think it's perfect tense. But she insisted that this is a past tense because the event of "knowing" is happened in the past.

Which one is true? And can you help give some explanation? Thanks.

  • I think including the word yet is at least stylistically clumsy there, if not actually "ungrammatical". You seem to be using it as a sort of "conjunction" between two subordinate/relative clauses with no main clause. The natural placement for the perfect would be Having had this phone for a year, I [just? obviously?] knew my phone camera has [an] automatic flash feature. I can't think of a context where "yet I have just known" would be idiomatically likely (I can just about contrive unlikely contexts, but it's not immediately "natural"). Jul 8, 2017 at 16:04
  • Note that you're using Having had X... as a "fronted relative clause" (always ended with a comma), which should normally be followed by a main clause in straightforward Subject+Verb+Object format. That's so Subject is properly associated with the earlier having (otherwise you've left a "dangling participle", which is what your version looks like to me). Jul 8, 2017 at 16:13
  • 2
    I do suspect the intended meaning is I just discovered. You can not convey that meaning with either I just knew or I have just known.
    – oerkelens
    Jul 8, 2017 at 16:41
  • @oerkelens but from your sentence, it makes that "just" is not always have to be interpreted as inducing "perfect tense" ? Jul 8, 2017 at 16:49
  • @ChenLiYong I am not aware of any rule like that about the use of just. If anyone told you that just should be followed by a perfect tense (present, past or future) they were wrong. Even your wife's I just knew is grammatically fine, it just means something completely different: All this time, I just knew something was wrong means that during all this time you had a distinct feeling that something was wrong.
    – oerkelens
    Jul 8, 2017 at 16:51

1 Answer 1


I have had present perfect this phone for a year but just now discovered simple past that it has automatic flash.

just now is understood to mean "a moment ago".

"just knew" is incorrect when the desired meaning is "just now found out".

"Know" does not mean "come to know" or "discover" or "learn" or "find out". It expresses the idea that you fully possess the knowledge.

  • Okay, so in the case of I use "discover", why it's "just now discovered" and not "have just discovered" ? Jul 8, 2017 at 16:53
  • 1
    It can be have just discovered.
    – TimR
    Jul 9, 2017 at 11:12

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