题目

Baby sign language is a growing movement.Pointing to a colorful flower, Tricia Campbell lifts her baby's soft hand, and rapidly moves it from one side of his nose to the other as she sniffs (嗅) loudly.“Flower！”she says loudly.Gregory smiles, looks carefully and says happily, “Flower！”It could be a year before Gregory, 4 months old, can speak, but now his mother hopes to communicate with her baby through sign language. Like others around the world, Campbell is part of a growing movement of parents teaching hearing babies simple signs to communicate before they can talk.The最多能装运3t汽油的油罐车，如果用来装水，一次可运水多少t？（ρ汽油=0.75×103 Kg/m3）