Grammar · Chapter 37
既然…就: since it's already so
既然 + what is already true，(A) 就 + what to do
既然 means “since, seeing that”: the first part is what has already happened or is known, the second is the conclusion or advice: 既然累了，就休息吧. 就 goes in the second part. Not the same as 如果: “if” is about something that may not be true.
Examples
- 既然你累了，就休息吧。 Jìrán nǐ lèi le, jiù xiūxi ba. Since you're tired, have a rest.
- 既然来了，就多住几天吧。 Jìrán lái le, jiù duō zhù jǐ tiān ba. Since you're here, stay a few more days.
- 既然你不想去，我们就不去了。 Jìrán nǐ bù xiǎng qù, wǒmen jiù bú qù le. Since you don't want to go, we won't go.