Questions & Answers about Kannst du mir bitte die Küchenrolle reichen?
Because this is a yes/no question in German. In German, yes/no questions usually put the finite verb first.
- Statement: Du kannst mir bitte die Küchenrolle reichen.
- Question: Kannst du mir bitte die Küchenrolle reichen?
So Kannst du ... ? is the German equivalent of Can you ... ?
Kannst is the du form of können, which means can / to be able to.
So:
- ich kann = I can
- du kannst = you can
- er/sie/es kann = he/she/it can
In this sentence, Kannst du ... ? is a very common polite way to make a request, like Can you ... ?