Using "Since" and "Then

This pattern works in two parts. The first part, 既然, introduces a fact that both you and the listener already know. It’s like saying, "Okay, we both agree on this fact." The second part, 就, introduces the result, the decision, or the suggestion that naturally follows that fact. It’s like a grammar traffic light—the first part is the green light of a known fact, and the second part is the car moving forward. You can't have one without the other if you want the sentence to feel complete. Without the 就, your sentence will feel like a cliffhanger, and nobody likes those.

1. 1Start with 既然 followed by the established fact or reason.
2. 2Place the subject. The subject can go before or after 既然. For example, 既然你... or 你既然... both work perfectly.
3. 3Add a comma to let the sentence breathe.
4. 4Start the second clause with the subject (if it's different) and then 就.
5. 5Finish with the action, suggestion, or result.
6. 6Basic Structure: 既然 + [Fact], [Subject] + 就 + [Action/Result].

You use this when the reason is already "on the table." Imagine you’re at a restaurant. Your friend says they aren't hungry. You’d say, "Since you aren't hungry, let’s just get coffee."

• Ordering Food: 既然你不吃肉，我们就点青菜吧。 (Since you don't eat meat, let's order vegetables.)
• Asking Directions: 既然你不知道路，我们就用地图吧。 (Since you don't know the way, let's use a map.)
• Job Interviews: 既然你有经验，我们就谈谈薪水吧。 (Since you have experience, let's talk about salary.)
• Daily Life: 既然下雨了，我就不出门了。 (Since it's raining, I won't go out.)

Don't use 既然 when you are talking about time. In English, we say "Since 2010," but in Chinese, that’s 从...以来. 既然 is strictly for logical reasoning, not for counting years or days. Also, don't use it if the reason is a total surprise to the listener. If you're explaining a cause-and-effect that they don't know yet, 因为...所以... is your better bet. 既然 assumes the "since" part is common knowledge between you two. Using it for a secret you just revealed would be like telling someone "Since I'm actually a spy..." before they even knew you had a job.

• Forgetting the 就: This is the most common slip-up. English speakers often say "Since it's raining, I'm staying home." In Chinese, you MUST have that 就 to link the two halves. Without it, the sentence sounds "naked."
• Using 所以 instead of 就: While 所以 (suǒyǐ) means "so," it doesn't pair with 既然. They are from different grammar families. It's like trying to wear a flip-flop on one foot and a hiking boot on the other.
• Subject Placement: While flexible, putting the subject after 就 is the standard. Don't put 就 before the subject (e.g., 就我就... is a big no-no).

People often confuse 既然...就... with 因为...所以....

• 因为...所以... (Because... therefore...) is for objective cause and effect. "Because I was sick, I didn't go."
• 既然...就... (Since... then...) is for subjective inference or suggestions based on a known fact. "Since you are sick, you should rest."

Think of 因为 as the "Why" and 既然 as the "Now that we know why, what's next?"