— There is an art festival in our school on Saturday.
— Oh, great! We'll _________ then.
A：have good time
B：play a good time
C：play good time
D：have a good time
①铁矿石②一氧化碳③焦炭④石灰石⑤孔雀石．
湖面如镜，划桨泛舟．以划船的人为参照物，小船是____ 的；水鸟掠过湖面时，翅膀上方空气流速____ （选填“大于”、“小于”或“等于”）下方，翅膀上下表面存在压强差，形成升力．
