Questions & Answers about nǐ xiān zài wàimiàn děng wǒ, wǒ hěnkuài jiù chūlái.
先 means first, before that, or for now.
In this sentence, 你先在外面等我 means something like:
- Wait outside first
- Go wait outside for now
It tells the listener to do that action before the speaker does the next action in the second clause.
This follows a very common Mandarin pattern:
subject + sequence/time word + location + verb + object
So here you get:
- 你 = subject
- 先 = first / for now
- 在外面 = outside
- 等 = wait
- 我 = me
So literally it is close to:
You first outside wait for me.
That sounds strange in English, but it is normal Chinese word order. Mandarin usually puts words like 先 before the main action, and location phrases like 在外面 before the verb too.
在 + place often tells you where an action happens.
So:
- 在外面等我 = wait for me outside
Here, 在 marks the location of the waiting.
Without 在, the sentence would not sound right in standard Mandarin here. The normal structure is 在 + location + verb.