write + while the chance lasts
kaku uchi ni
while the chance lasts; before the situation changes
meaning: while still writing
日本にいるうちに、一度は富士山に登ってみたい。
nihon ni iru uchi ni, ichido wa fujisan ni nobotte mitai.
I want to climb Mt. Fuji at least once while still living in Japan. neutral
冷めないうちに食べてね。
samenai uchi ni tabete ne.
Eat it before it gets cold. casual