could you please maintain silence for a while?
-so, I have to find the error in this sentence? The book in which I found this says: the error is with the 'could you' part, but doesn't explain it further. As a result of which I am confused now. Isn't 'could' used in making requests as in this sentence :Could you lend me five pounds until tomorrow? I know there is nothing grammatically wrong with the sentence just mentioned . So, how using 'could' in the first sentence be considered wrong? Is using 'could' in a sentence where there is also a 'please' considered wrong? Thanks in advance.