744 - と～た ([coincidence])
JLPT N3: と～た・～たら～た (just when)
Short lesson, スタート！
In our last N4 lesson, we saw that following「Vる ＋ と」or「Vたら 」with a past-tense phrase is a way to describe the discovery of something which had happened or was happening.
A similar pattern can also be used to show that two things happened at the same time.
We can follow「Vている ＋ と」with a phrase in the past tense, which makes it sound like the things occurring in the two phrases are a coincidence — specifically, the past tense phrase coming after と sounds unexpected:
せんたくもの を ほしている と、 とつぜん あめ が ふりはじめました。
I was hanging up the laundry when it suddenly started raining.
Literally: “laundry (items) + を + is hanging up to dry + と, + suddenly + rain + が + started falling.”
Technically, we just need to put「Vる ＋ と」but「Vている ＋ と」is the most common form in which you're likely to encounter this grammar.
Since the second sentence is talking about unexpected events, it will not include an action that is being performed by the speaker. After all, an event can't be "unexpected" if we willed it to happen, right?
We can also use「Vていたら 」in this type of construction, which has a more colloquial sound to it than「Vている ＋ と」does:
いえ の おくじょう で ひるね を していたら、 はち に さされました。
I was taking a nap on the roof when I got stung by a bee.
Literally: “house + の + rooftop + で + taking a nap + を + when I was doing, + bee + に + was stung / was pricked.”
Let's see two more examples...
おんせん に つかっている と、 さる の カップル が あそび に きました。
We were in the onsen [hot spring] when a pair of monkeys came to see us.
Literally: “onsen / hot spring + に + am soaking + と, + monkey + の + couple (e.g. boyfriend and girlfriend) + が + came to play / hang out (=playing + に + came).”
かみ を かわかしていたら、 かれし から でんわ が かかって きました。
I was drying my hair when my boyfriend called me.
Literally: “hair + を + when I was drying, + boyfriend + from + got a phone call (=phone + が + get / have put on [and] + came).”
What do you think? Nice, short lesson, yeah?
But that doesn't mean you shouldn't take your time with it. Every single word in our example sentences is very common. I'd recommend making sure that you know all of them.