Again and again
The word again can be translated into 再 zài or 又 yòu but the 2 of them are not exactly interchangeable. Let's look at their subtle differences.
When Thor, Prince of Asgard, arrived on Earth, he liked the coffee so much, he asked for another serving. If you were him, how would you say it?
Option (A) : 再来一杯!
or
Option (B) : 又来一杯!
From the 2011 Marvel film
When Team Rocket's plans are foiled, they are usually sent hurling off into the sky / space / somewhere, saying the signature line: "looks like Team Rocket is Blasting off again". If you were Jessie or James or Meowth, how would you say it?
Option (A) : 我们又被炸走了!
or
Option (B) : 我们再被炸走了!
If you have 2 hours to burn, click on the YouTube link to bear witness
to the indefatigable spirit shown by Team Rocket
In both instances, Option A is correct.
再 zài refers to the action that will occur in the future. When Thor asked for the 2nd serving, that 2nd mug of coffee hasn't been given right? It's something he will receive (and will drink) in the future.
又 yòu refers to the action that has already occurred. Team Rocket has been sent blasting off countless times in the past. So when it happens to them again, the correct word to use is 又.
Here's a summary to help you remember the differences:
再 and 又 may also be used in a negative way to describe non-occurrences. In such situations, this is how you can use them:
