洒水车在水平路面上匀速前进并洒水时，它的动能____，机械能____。(选填“变大”“变小”或“不变”)
下列哪种生物可以监测空气的污染程度（ ）
— Would you like to go for a picnic to enjoy the fresh air outside this weekend? — __________. It will be a sunny day.
