How to Say No thanks, I'm just looking in Czech with how to pronounce and transliteration in English?

English to Czech

• Can I see this, Please? Mohu vidět, prosím?
• I would like a piece of cake Chtěl bych kousek dortu
• I'm single Jsem svobodný
• Can I have a refund, Please? Mohu mít náhradu, prosím?
• Are you open on Sunday? Máte otevřeno v neděli?
• Can I help you? Mohu vám pomoci?
• Could I have a carrier bag, Please?
• I'd like to return this book, Please Já bych se chtěl vrátit tuto knihu, prosím,