题干

图甲是在高速公路上用超声波测速仪测量车速的示意图,测速仪发出并接收超声波脉冲信号.根据发出和接收到的信号间的时间差,测出被测物体的速度.图乙中p1、p2是测速仪发出的超声波信号,n1、n2分别是p1、p2由汽车反射回来的信号.设测速仪匀速扫描,p1、p2之间的时间间隔△t=1.0s,超声波在空气中传播的速度是v=340m/s,若汽车是匀速运动的,设汽车在接收到p1、p2两个信号之间的时间内前进的距离是△x,汽车的速度是v,则根据图可知(  )

A:△x=17m

B:△x=34m

C:18.9m/s

D:17.9m/s

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A,D

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    I've always been a very anxious person—easily worried and stressed. And I've always been losing things.

    I'm not sure what exactly 1 my desire to attempt a more organized lifestyle. I started to attempt to be less 2and more organized. Instead of cleaning my room twice a year, I 3to do it about 4-6 times a year.

    Over a couple of years I started cleaning my room more, and I even 4using a planner on a daily basis: It took years to institute these actions into habits, 5I wasn't aiming for habits. I was simply trying to be a little 6—a little bit at a time.

    After I 7multiple outfits(装束) at home, 8leaving clothes on my bed and shoes on the floor, I put everything away before going out. After cooking and eating, I put everything in the dishwasher or wash it by hand. Each of these tasks only takes a few minutes. And not only does this 9immediate clutter(杂乱), but it's also much 10to deal with one mess at a time rather than leaving it all to turn into a giant mess. Organization creates ease, and ease creates organization, both of which 11to lower levels of stress and anxiety! And spending less time feeling 12means having more time to be happy, productive and present.

    Since I began intentionally being more organized, I find I have more 13to adopt other new habits to maintain(保持) and strengthen a calmer and cleaner lifestyle. Good habits result in more good habits, which help to create a better and happier you.

    If you find yourself worried, stressed or anxious beyond your control, then 14what you can—your 15. Create a comfortable, clean and calm space where you can escape from the outside world, and it doesn't have to be all at once.