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Daily lessons · Day 22 of 90

Past tense: what you did

Talk about yesterday

Everything you have said so far has been about now or about the future. Today you get the past, and it is one of the easier things in Japanese: no irregular verbs to memorise, no auxiliary to add, just a different ending on the same stem you already use. The one trap is adjectives, which have their own past and do not borrow です's.

Verbs in the past

Swap ます for ました. That is the whole rule:

tabemashita.
I ate.
From たべます. Also covers have eaten and did eat.
ikimasen deshita.
I didn't go.
ません plus でした. Long, but built from parts you know.
kinō nani o shimashita ka.
What did you do yesterday?
します to do, so しました did.
tōkyō ni ikimashita.
I went to Tokyo.
に marks the destination, as on day 6.
Why it works

Japanese has one past tense where English has several. ました covers ate, have eaten, had eaten and did eat, and context supplies the rest. That is a genuine simplification, and it is worth noticing because English speakers often go looking for a perfect tense that does not exist here.

Nouns and な-adjectives in the past

です becomes でした, exactly as you would hope:

kinō wa yasumi deshita.
Yesterday was a day off.
やすみ a rest or a holiday.
benri deshita.
It was convenient.
な-adjectives behave like nouns, so they take でした.
hima ja nakatta desu.
I wasn't free.
The past negative. じゃない plus かった.
Why it works

Notice that じゃなかった is just じゃない with the い-adjective past ending stuck on it. Japanese does this constantly: it builds long forms out of short ones you already know rather than inventing new words. When a form looks intimidating, try taking it apart before you memorise it.

い-adjectives in the past

This is the one that catches people, so it gets its own section:

tanoshikatta desu.
It was fun.
Drop the い, add かった. Never たのしいでした.
samukunakatta desu.
It wasn't cold.
くない becomes くなかった.
yokatta desu.
It was good. / I'm glad.
From いい, irregular as always. Also means I'm relieved.
oishikatta desu.
It was delicious.
Say this at the end of any meal. It is expected and appreciated.
Why it works

たのしいでした is wrong for the same reason たかいでした was wrong on day 15: the い-adjective carries the tense itself, so です has nothing left to do but be polite, and politeness has no past. If you catch yourself reaching for でした after an い-adjective, the かった is what you want.

kinō nani o shimashita ka.
What did you do yesterday?
tōkyō ni ikimashita.
I went to Tokyo.
tanoshikatta desu.
It was fun.
oishikatta desu.
It was delicious.

Check yourself

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