问题
单项选择题
手提一根不计质量，下端挂有重物的弹簧，竖直向上作加速运动，当手突然停止运动瞬间，物体将( )。
A．立即停止运动
B．向上作加速运动，处于超重状态
C．向上作减速运动，处于失重状态
D．向上作匀速运动
答案
参考答案：B
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手提一根不计质量，下端挂有重物的弹簧，竖直向上作加速运动，当手突然停止运动瞬间，物体将( )。
A．立即停止运动
B．向上作加速运动，处于超重状态
C．向上作减速运动，处于失重状态
D．向上作匀速运动
参考答案：B
I live in the north of New York. One day last 31 when we received our first snow, I looked out and knew that I had to stay at home. An hour later, I tried to go out to walk my dog. But to my 32, I found my sidewalk and path were cleaned. I had no idea 33 did this good deed（事情）. I looked over to my neighbor’s sidewalk. There stood the husband with also surprising looks on his face. I 34 him who did it. He also had no idea. About a week later, we had another snow and I 35 to find the snow angel (天使). It was a good plan, but I got busy inside and 36 to keep a look out. When I remembered to look out, the sidewalk was 37 again. Now I believe determined (坚决的) to find my snow angel. I asked everyone I knew in the neighborhood. I had 38 here for only three years and only knew some of them. So once again my snow angel got away. I waited for the third snow. While I was reading I 39 some noise. Tears came to my eyes. I found my snow angel was an 8-year-old boy. He lives a few houses away from me, 40 he came here to clean my side-walk. For a short time I know , he is an angel for everyone, not only for me.
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