According to internet sources and my Chinese friend living in Japan, there
isn't. However, can someone provide more evidence on this issue? If there is
no grammatical distinction, how can we distinguish these two tenses? I mean,
how do we know if one sentence is translated to "did something", while the
other to "have done something"?

Edit: I have a new question but I am not sure to start a new one or add to
this. My question is on the construction of english tenses in Japanese. I know
there is no one-to-one correspondence. But I am hoping to reconstruct them as
accurate as possible. Simple past is ta-form. Present perfect is もう plus
た-form. Past perfect is もう plus ていた. Is this correct?
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grammar tense past
Is there a distinction between ‘did" and "have done" in Japanese?
Since your examples are in English, I should point out that the technical
distinction you are making is between `the simple past` (a past verb form with
no auxiliary attached - 'did') and `the present perfect` (a verb form with
have/has + past participle - 'have done'). Japanese verbs operate very
differently to this. Although there is a past tense in Japanese, there is no
such thing as a past participle in Japanese. So there is no direct equivalent
of 'have done'. Therefore there is no **technical** difference between 'did'
and 'have done' in Japanese (i.e. a verb form which explicitly distinguishes
the two as in English).

In other words, both the following translations are possible for the sentence:

> 宿題{しゅくだい}をした。  
>  I did my homework. / I have done my homework.

However, that is not to say that there is no way at all to convey the
difference. Depending on what you want to say, it will be possible to include
contextual information like time-markers, auxiliary verbs, etc, which makes
the intended meaning clearer. But you would need to provide more specific
examples of what you want to say in order to highlight the different ways you
could express it in Japanese.
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While there's no distinction grammatically in the positive sense, there is a
distinction in negations:

> 朝食は、 何も食べなかった (I did not eat anything for breakfast)
>
> 朝から、何も食べていない (I have not eaten anything since breakfast)

As shown in the preceding examples, for negations, the た-form is used for the
simple past (did not) and the ている-form is used for present perfect (have not
done).

Some words that help indicate whether it means simple past or present perfect
include:

  * ご飯は **まだ** 食べていない - have not done (negation present perfect)
  * ご飯は **もう** 食べた - have done (affirmation present perfect)

Here's a reference on this: <https://www.wasabi-jpn.com/japanese-grammar/past-
tense-and-present-perfect-tense-with-the-ta-form/>.
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