Safety must come first. During the coming summer vacation, some of us may travel to other places. To keep safe during the journey, we should      .  

     ①avoid eating raw(生的)and cold food

     ②obey the local traffic rules

     ③swim in the dangerous area

     ④never stretch our hands out of the window when taking a bus

     ⑤ tell strangers our personal information

如图①，一次函数y=kx+b的图象与二次函数y=x²的图象相交于A，B两点，点A，B的横坐标分别为m，n（m＜0，n＞0）．