I've studied English for only a few years so my English may sound strange. I'm sorry if what I wrote doesn't make much sense.
The other day at my English class, my teacher corrected my answer "I will have finished my homework before noon." into "I will have finished my homework by noon.
Then my questions are as follows.
・ In general, can "will have done... " and "before ..." be used together?
・ If not, why? What makes it incorrect?
・ If it's OK, which of "by" and "before" sounds more natural?