1.
whole life, lifetime
The entire span of one's life from birth to death.
一生の思い出になった。
It became a memory for a lifetime.
一生の友達ができた。
I made a lifelong friend.
一生に一度の経験です。
It's a once-in-a-lifetime experience.
Common expression
祖父の一生は波乱万丈で、色々な苦労を乗り越えてきた。
My grandfather's life was eventful, and he overcame many hardships.
あの旅行は一生の思い出になりました。機会があれば、またあの場所を訪れたいです。
That trip became a memory for a lifetime. If I get the chance, I'd like to visit that place again.
2.
for life, forever
For the rest of one's life, permanently.
一生忘れません。
I'll never forget it for the rest of my life.
この仕事に一生をかける。
I'll devote my whole life to this work.
一生あなたを愛します。
I'll love you forever.
一生会えないかもしれないと思うと、寂しくなる。
When I think we might never meet again, I feel lonely.
あの日先生に言われた言葉を、私は一生忘れないだろう。
I will probably never forget the words my teacher said to me that day.
一生 means one's entire life or lifetime.
COMMON PATTERNS:
- 一生に一度 (once in a lifetime)
- 一生忘れない (never forget)
- 一生をかける (devote one's life to)
- 一生の仕事 (life's work)
USAGE:
- Can be used as noun: 一生の～ (lifelong ~)
- Can be used adverbially: 一生～ない (never in one's life)