如图所示，甲、乙、丙三辆车行驶在平直公路上，车速分别为5m/s、8m/s、10m/s．当甲、乙、丙三车依次相距6m时，乙驾驶员发现甲车开始以1m/s²的加速度做匀减速运动，于是乙也立即做匀减速运动，丙车亦同样处理，直到三车都停下来时均未发生撞车事故．

    Hello, I'm Danny____is my favourite colour. My favourite____ are shorts. I don't like math____is my favourite subject. I like hamburgers for ____.My favourite school work is to____ with my friends. What about you?

已知a、b是有理数，且a＞b，则下列式子正确的是（　　）