补全对话。
上午,Dan与Joan在教室里谈话。
Dan: 1 ______, Joan!
Joan: 2 ______! Sit down, 3 ______.
Dan: 4 ______.
Joan: 5 ______ 6 ______ 7 ______?
Dan: 8 ______, thank you. 9 ______ 10 ______?
Joan: I'm fine, too.
Dan: Look, 11 ______this?
Joan: 12 ______a football.
1.______ 2.______ 3.______ 4.______ 5.______ 6.______
7.______ 8.______ 9.______ 10.______ 11.______ 12.______