Qfyilyi

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"?

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/.

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.