在我国的经济大舞台上，活跃着多种所有制经济，                 是我国社会主义经济制度的基础。（    ）

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                              汽车安全带

    汽车安全带是用于保护驾乘人员安全的装置，如图甲．

    安全带结构一般由软带、等部分组成．汽车正常行驶时，卷带装置中的卷收器借助弹簧，如图乙，使软带随身体的移动而自由伸缩且不会松弛．当紧急制动、碰撞或车辆行驶状态急剧变化时，安全带能在人尚未移动时拉紧软带，将乘员紧紧地绑在座椅上，待冲击力峰值过去时，适当放松安全带，避免因拉力过大造成二次伤害，同时卷收器内的敏感元件将驱动锁止机构锁住卷轴，使软带固定在某一个位置上，有效保护乘员的安全．

汽车上都设有安全带未系提示系统．系统中有两个开关，座椅下开关S₁和插卡开关S₂．当乘客坐在座椅上时，开关S₁闭合，表盘上的指示灯亮；系上安全带时，开关S₂闭合，指示灯熄灭，有效提醒驾乘人员系好安全带．

    On the second Sunday in May is Mother's Day. American children of all ages give their mothers something special. It is the day children, young and old, try to show their love to mothers.

    England was the first country to set a day to mothers. In the United States, Mother's Day became an official(正式的) holiday in 1910.An American girl, Anna, asked their governor(州长) to set a festival for mothers that they love. And they set the second Sunday in May as Mother's Day and a year later all the other states celebrated it.

    On Mother's Day morning some American children serve their mothers breakfast in bed. Other children will give their mothers presents which they made themselves or bought in stores. Adults give their mothers red carnations(康乃馨), the official Mother's Day flower. If their mothers left the world they may bring white carnations to their grave sites (墓地). This is the busiest day of the year for American restaurants. On this special day, family members do not want Mom to cook dinner!

①是公民赖以生存的基础

②可以保障合理的生活水平

③有利于实现自身价值

④能够为国家和社会做出贡献