I'm trying to find 就 used as "at once" in a sentence so that I can add it to my flashcards but the only sentence I've found like that would be "你现在就去做". Issue is, 现在 already means "now" so that makes 就 redundant in the sentence doesn't it? Can anyone give me a proper sentence that uses 就 to mean "at once"?
就 in 你现在就去做 functions as the adverb "just".
你现在去做 = you go do it now
你现在(就)去做 = you (just) go do it now
Example of 就 = at once; right away:
吃完飯去 = go after finish dinner
吃完飯(就)去 = go (right away) after finish dinner
吃完飯 is the requirement. Once this requirement is met, then 去 occur at once
完成工作付工資 = when you finished work, I will pay your service fee
完成工作(就)付工資 = when you finished work, I will pay your service fee (right away)
完成工作 is the requirement . Once this requirement is met, then 付工資 occur at once
Since 你现在就去做 doesn't include a requirement, 就 doesn't carry the meaning of 'at once; right away'
If it was 你等到明天就去做 (you go do it at once when tomorrow comes); 等到明天(wait till tomorrow arrives) would be the requirement.
Language has built-in redundancy. I think that is in order to make sure the message gets across.
You might ask: When exactly is 'now'?
你现在就去做 Go and do it now, immediately!
In this case, I think 就 is emphatic: 你立刻去做。or 你立刻就去做。
就 is a Pandora's box!
At once originally (early 13c.) meant "simultaneously," later "in one company" (c. 1300), and preserved the sense of "one" in the word; the phrase typically appeared as one word, atones; the modern meaning "immediately" is attested from 1530s.
'at once' would normally be translated as 赶快， 马上。
This sentence has 就：
天一下儿就冷了。 All at once the weather turned cold.
but 'at once' comes from ‘一下儿’