Expressing "Since" With "既然jìrán"

既然jìrán means "since," and is often followed by 那nà or 就jiù to mean "since...then....".

The suggestion or inference deduced from the first "fact" can come in the form of rhetorical question. In this case, (那nà / 就jiù / 那就nà jiù) can be omitted.

既然jìrán + Fact, (那nà / 就jiù / 那就nà jiù) + Rhetorical Question

Jìrán yǐhòu huì líhūn, xiànzài wèishéme yào jiéhūn ne? 

既然以后会离婚，现在为什么要结婚呢？

Since there will be divorce in the future, why get married now?

Jìrán fēnshǒule, wèishéme hái yào jiànmiàn?

既然分手了，为什么还要见面？

Since we broke up, why do we still need to meet?

既然jìrán + Fact, (那nà / 就jiù / 那就nà jiù) + Suggestion / Inference

Jìrán míngtiān huì xià yǔ, nà wǒmen jiù hòutiān qù páshān ba! 

既然明天会下雨，那我们就后天去爬山吧！

Since it will rain tomorrow, let’s go hiking the day after tomorrow!

Jìrán nǐ de lǎogōng nàme ài nǐ, nà tā yīdìng huì zhīchí nǐ de.

既然你的老公那么爱你，那他一定会支持你的。

Since your husband loves you so much, he will definitely support you.

Jìrán lǎobǎn méiràng nǐ qù，nǐ jiù bùyào qù le.

既然老板没让你去，你就不要去了。

Since your husband didn't let you go, you shouldn't go.

Note：If there is a subject, 那nà should be put before the subject, however, 就jiù should be put after the subject.