you're finished vs. you finish

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hello,

I have some questions on the sentences below:

  1. Will that be a sweater when you’re finished knitting it?
  2. Will that be a sweater when you finish knitting it?
  1. I think both sentences are right. However, I don’t know why 1) uses “be finished” there. Is there a nuance difference? Or, is 1) just wrong? Please let me know!

Thanks in advance,
sweetpumpkin

2

The first is less formal and can most often be heard in speech. Grammatically it should be “… when you’ve finished knitting it”