From How to appropriately pair tenses in subordinate and main clauses?, one of the answers provides:


Problem: Is this sentence technically ambigious, in that it could mean: "I ate before I brushed my teeth" OR "I ate before I brush my teeth"? Note that in second interpretation: (i) the brushing of teeth is in the non-past tense, and (ii) it's ambigious whether or not the brushing has happened yet or not.

The general pattern (if my understanding is correct) is

(Non-Past Tense Action A)前に(Past Tense Action B)

could either mean

  1. I did action B before I did action A. The usual/contextual interpretation.

  2. I did action B before I do action A. Also technically acceptable?

Question: While I understand that, in context, interpretation (1) is usually the more reasonable one, technically speaking is interpretation (2) also valid?

NOTE: IMABI's article on 前 provides examples in which interpretation (1) is exclusively chosen. For example:


I bought traveler's checks before I went on my trip. (Couldn't this also be "before I go on my trip")?

  • 1
    It seems more irrelevant than ambiguous because the sentence is not meant to say whether A has happened by the time of utterance.
    – aguijonazo
    Nov 4, 2022 at 23:02
  • Is I did action B before I do action A a valid English sentence? Anyway before specifies the order A < B, and if B is past, then A is past as well.
    – sundowner
    Nov 5, 2022 at 1:32
  • 1
    @sundowner Here isn't the situation B < A, and all we know is that B is past (so we can't conclude A is past, necessarily)?
    – George
    Nov 5, 2022 at 2:06
  • @sundowner The sentence "I did action B before I do action A" definitely isn't an idiomatic English sentence (and possibly invalid). With that said I think it could be converted to one that is valid? Perhaps: "Having done action B, I now do action A".
    – George
    Nov 5, 2022 at 2:09
  • 1
    I wouldn't say it's wrong but one might argue it's a case of "added in translation". When you say a sentence like that in Japanese, you are putting yourself at such a point in time where B has completed and A is yet to happen. Hence the past tense for B and the non-past tense for A. It's so natural in the perspective of relative tense. When you translate it to English, however, you need to switch perspectives and speak from the point of the absolute "now". This requires you to determine whether A has already happened by that time or not. If English speakers see it as ambiguity, I guess it is.
    – aguijonazo
    Nov 6, 2022 at 0:21

1 Answer 1


I would argue that neither of those interpretations is actually technically the most accurate/direct translation into English, and instead that (non-past action) + 前に actually has basically the same meaning as using the gerund form ("before (verb)ing") in English:

歯を磨く前に食べた -- "I ate before brushing my teeth"

In this sense, I think it is really exactly as precise or ambiguous as this English sentence is. It says that the time you were eating was chosen so that it would be before you brushed your teeth, but does not say anything about when the brushing of the teeth might have happened or happen. The strong implication is that brushing teeth would occur shortly after eating, though, and therefore if you ate some time ago it is assumed that you have already brushed your teeth by now.

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