补全对话。 A: What's the 1. today, Mary? B: It's May 2. . A: Oh, tomorrow is your mom's birthday. Do you 3. ? B: Of 4. , I do. How shall we celebrate it? A: First 5. all, a birthday gift. 6. 7. her a beautiful sweater? B: That's a good 8. . I think it will make 9. happy. A: Er…shall we have a special dinner? B: Yes, Dad. How about a Chinese dinner? A: OK, I'm going go buy a sweater. You can cook at home. B: Oh, don't forget to buy a 10. . (     )1.A.date (     )2.A.twenty-first (     )3.A.forget (     )4.A.that (     )5.A.of (     )6.A.What (     )7.A.buy (     )8.A.question (     )9.A.you (     )10.A.birthday cake B.day B.twenty-one B.remember B.so B.at B.Which about B.to buy B.problem B.me B.sweater C.number C.twentieth-first C.think C.this C.in C.What about C.buying C.idea C.dad C.chicken D.month D.twentieth-one D.think out D.course D.for D.When about D.bought D.answer D.her D.flower