Crazy question :P

I have one weird question.
Can you tell me some website like this where the questions and answers cant be found with using google ? (some "have to register before watching" I guess) .
I´d like to use this site for correcting mistakes in english homework, but I dont want to give my teacher (who would be suspicious of my 100% correct work) chance to write few words in order from the homework in google and see the previous not corrected version
Thanks for reading this silly problem