write + when
kaku toki
when; at the time of
meaning: when writing
子どものとき、ここは全部田んぼだったんだよ。
kodomo no toki, koko wa zenbu tanbo datta n da yo.
When I was a kid, this whole area was rice fields. casual
大阪へ行くとき、駅でお弁当を買った。
oosaka e iku toki, eki de obentou o katta.
I bought a boxed lunch at the station when going to Osaka (on the way there). neutral