听力原文:M: I'd dike some red roses. W: Is it your wife's birthday? M: No, it's our wedding anniversary. She really likes roses. So I give her some every week. I just wish they would stay fresh longer than they do. W: If you put a little sugar in the water they will stay fresh for days. M: Really? I want to try to use white vinegar in the water and it helped a little. W: Sugar is even better. M: It is worth trying, I will tell my wife. How much do I owe you? W: Let's see. They are $ 10 a dozen. So that will be $ 5.00. M: OK. Here you are. W: Thank you. Here are the flowers. How often does the man give his wife roses?