In China, many people often take ______ own bags when shopping.
That's very kind ______ you. I know it's very hard _______ you to do that.
David used to _____________ in the afternoon.
How do you study _______a test? I study _______working with friends.
--- Could you tell me? --- Certainly. In 20 minutes.
---How much did the new watch your sister? ---She 350 yuan for it.