thirty years old
他在自己三十岁生日那天自杀了。
He killed himself on his thirtieth birthday.
人一生只有一次三十岁
You only turn thirty once in your life.
— 摩托日记 (2004)
三十岁买房子
Buy a house at thirty.
— SoulMate (2016)
汤姆今年三十岁。
Tom is thirty years old this year.