题干

下列叙述正确的是(   )

A:钠在空气中燃烧生成淡黄色的Na2O2

B:将SO2通入过量BaCl2溶液可生成BaSO3沉淀

C:新制氯水显酸性,向其中滴加少量紫色石蕊试液,振荡后溶液最终呈红色

D:点燃的镁条插入盛有CO2的集气瓶中,立即熄灭

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答案(点此获取答案解析)

A

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笑,不苦口的良药

梁姗姗

       ①医学研究证明,笑具有激活人体某些基因的功能。人们通常认为,基因是恒定不变的。但事实上很多基因常常处于休眠状态,或者没有积极地制造蛋白质,通过某种形式的刺激,可以把它们唤醒,笑就是其中一种刺激。

       ②斯坦福大学研究人员曾经对心脏病患者做了一次测试。研究人员首先找来20名心脏病患者,观看半小时分别取自喜剧和悲剧的两部影片片段,两次观看的间隔时间在 8 个小时。然后,通过超声波测量患者肱动脉的血液流速,结果 20 人中有14人在看过令人痛苦的电影片段后,血流速度放缓,但在观看电影中的搞笑片段后,有 19 人血流加速。最后,对患者进行的心电图测试表明,患者观看悲剧电影时对心脏血流速度产生的影响,类似于做心算的影响;而观看喜剧电影相当于进行了一次有氧运动。

       ③人生来就会笑,但很少有人知道,人持续大笑_____次,对心脏的血液循环和肺功能的锻炼,相当于划____分钟船的运动效果。只要发笑,嘴角和颧骨部位的肌肉便跟着运动,将嘴和两眼向上提拉。这种面部按摩,可以阻止面部线条下坠。每笑一声,从面部到腹部有80块肌肉参与运动,不仅具有减少皱纹的功效,还是一种有效的减肥方式。笑,不正是一种保持青春的美容操吗?

       ④不仅如此,笑还是一种最为简单而有效的健身运动。开怀大笑时,随着呼吸肌群的运动,使胸腔和支气管先后扩张,增强了换气量和血氧饱和度,有助于心脏供氧。笑作为一种有效的深呼吸运动,已被越来越多的人们所认识。大笑伴随着腹部肌群的起伏,又是一种极好的腹肌运动。腹肌在大笑中强烈地收缩和震荡,不仅有助于把血液挤入胸腔静脉,改善心肌供血,对胃、肠、肝、脾、胰等脏器也是一种极好的按摩。一张一弛之间,使劳累的肌肉在运动中得以放松。

       ⑤生活需要笑声,的确,每一个人都需要放缓脚步,静观周围美好的事物,凝神谛听大自然的天籁,让绷紧的脸庞舒缓,皱紧的眉宇打开,让微笑在脸上绽放,才能融解人们彼此之间的冰霜和风寒。引人发笑或是接受别人开的玩笑,这意味着你掌握了社会密码,它可以帮助你解决争端,使别人接受你的想法,从而更好地融入集体。通过微笑促进人类心理健康,在人与人之间传递愉悦与友善,增进社会和谐。

       ⑥笑虽然不用花钱买,不必向人借,却需要“投入”。常和爱笑的人相处,置身其中立马受到感染;注意搜集整理引人发笑的笑话、幽默等资料,品味其间自是忍俊不禁;只要有时间,尽可能去欣赏喜剧、相声之类让人发笑的艺术,使自己多笑几声。

       ⑦朋友,今天你微笑了吗?

     【注释】①肱:gōng 胳膊上从肩到肘的部分,也泛指胳膊。②颧:huán 眼睛下边两腮上面突出的骨头。

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Grandparents Answer a Call

    As a third generation native of Brownsville, Texas, Mildred Garza never planned to move away. Even when her daughter and son asked her to move to San Antonio to help their children, she politely refused. Only after a year of friendly discussion did Ms Garza finally say yes. That was four years ago. Today all three generations regard the move as a success, giving them a closer relationship than they would have had in separate cities.

    No statistics show the number of grandparents like Garza who are moving closer to the children and grandchildren. Yet there is evidence suggesting that the trend(趋势)is growing. Even President Obama's mother-in-law, Marian Robinson, has agreed to leave Chicago and into the White House to help care for her granddaughters. According to a study grandparents com., 83 percent of the people said Mrs. Robinson's decision will influence the grandparents in the American family. Two-thirds believe more families will follow the example of Obama's family.

    “In the 1960s, we were all a little wild and couldn't get away from home far enough or fast enough to prove we could do it on our own,” says Christine Crosby, publisher of Grand a magazine for grandparents. “We now realize how important family is and how important it is to be near them, especially when you're raising children.”

    Moving is not for everyone. Almost every grandparent wants to be with his or her grandchildren and is willing to make sacrifices, but sometimes it is wiser to say no and visit frequently instead. Having your grandchildren far away is hard, especially knowing your adult child is struggling, but giving up the life you know may be harder.