Opportunity knocks only once.

机会只有一次。

youdao

Of course I wont't chill out. Opportunity knocks only once.

我当然不会罢手的，机会难得嘛。

youdao

Dad often says that opportunity knocks only once, so one must take it when it comes.

爸爸总说机不可失、时不再来，有了机会一定要把握住。

youdao