Definition
Used to indicate that someone is experiencing a period of good fortune or success.
你真幸运！
You managed to get tickets at the last minute! Your luck's in!
你在最后一刻买到票了！你运气真好！
She wasn't expecting to get the job, but she did. Your luck's in!
她本来没指望得到这份工作，但她得到了。你运气真好！
You found a brand new one when they were all sold out. Your luck's in!
在所有东西都卖光的时候，你竟然找到了一个全新的。你运气真好！