Past tense ...でする vs. past tense copula です confusion

Question

Maybe this is a stupid question, because very likely it is possible for advanced learners to distuiguish this. However, in the present tense ...でする (particle で) and ...です (copula) are distinct, while in the past tense they sound the same.

My current way to cope with this problem is to search in e.g. Google for expressions using the present tense, i.e. either です or で+する and compairing the number of found pages.

Example phrase: 思い出でした

Google hits for

思い出でする: 22
思い出です: 2.7 million

Clearly, copula wins over the other "possibility". This is rather awkward. Especially if there are terms that are less frequently used so Google returns either way few pages. Is there an easier way I am not seeing?

Thanks!

Answer 1

思い出でする means "to do something as(because of) a memory", this で is a postpositional particle that is used for "cause", "reason". For example, 彼女と初デートの場所でキスを思い出でしたい.

思い出です means "Something is a memory", です is a copula.

思い出でした can mean the both meanings. For example, 彼女と初デートの場所で、キスを思い出でした(I kissed my girl friend at the our first date place as a memory), 彼女とのファーストキスは、良い思い出でした(My first kiss with my girl friend was a good memory).

Answer 2

思い出でする looks like a typo to me. The first four hits on Google are echoes of the same single posting, such as here. The verb phrase omoide suru (to have a memory about something) is spelled in kanji/kana as 思【おも】い出【で】する. The phrase 思い出でする would have to be read as omoide de suru, which is grammatically broken. There are cases where 思い出でする could be read as omoide (noun, "memory, recollection") de (particle, often instrumental, "with, by means of") suru (verb, "do"), as part of a larger phrase, but this seems unlikely and the semantics (meaning) doesn't work very well.

Meanwhile, 思い出です would be read as omoide desu. This is grammatically correct, and works out to: "[something] is a memory." I'm showing 2.94 million hits for this, though, not 22, compared to just 26 hits for 思い出でする. This is nearly backwards from what you found -- I'm not sure how you're getting your hit numbers?

Looking back at your original phrase, 思い出でした would be read as omoide deshita, and it would mean "[something] was a memory". On its own, there is no confusion between past-tense copula でした (deshita) and partcle + past-tense "do" でした (de shita), simply because the latter doesn't make sense.