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

“一切传统均不再神圣。无政府主义、自由主义、唯物主义、实验主义……以及最新的布尔什维克主义，均找到支持者。”上述情景出现于（  ）

在平面直角坐标系中，抛物线y=﹣$\frac{1}{2}$x²+bx+c与x轴交于点A，B，与y轴交于点C，直线y=x+4经过A，C两点．