题干

如图所示,一水平宽度为d、竖直范围足够大的匀强电场,场强为E,一带电量为+q的粒子以不同的初速度从一侧垂直电场方向进入电场,不计重力.则该粒子(   )

A:能飞出电场,且初速度越大,飞出电场时的速度变化越小

B:能飞出电场,且初速度越小,飞出电场时的速度变化越小

C:当初速度小于某一个值,不能飞出电场

D:当初速度大于某一个值,不能飞出电场

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A

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      A couple of weeks ago, I made a trip to Toronto with my granddaughter who just turned three years old. The two of us were on our way to  1   her parents, and my wife—her  2    who had been gone for over a week. We were all anxious to  3    again and as I pulled out of Mamere and Papere's driveway in Chelmsford, Hailee and I were both  4    about the trip and couldn't wait to arrive at our   5.

When we completed the “SEVEN”-hour trip to Toronto later that day, the reunion was absolutely  6 and I can sincerely say I enjoyed every single minute of that   7     journey.

      Hailee is at that “I want to  8  it myself” stage of her life. And if you can just get over the “hurry-up syndrome” we acquire as  9, it is wonderful to witness. Who knew that putting a straw into the  10  in a juice box for the very first time could be such an earth-shattering (惊天动地的) event? Or being  11  enough to actually open the fridge door for the first time? Or putting on your own  12  on the right feet would be so  13?

      I'll never forget the look on her face the day she was able to  14 into my truck by herself. She finally  15 on my seat, holding onto the steering wheel (方向盘) and declared 16, “I did it!” And when she could actually put her own seat belt on—what a(n)  17!

    Have you ever watched a three-year-old 18 to sip a McDonald's milkshake through a straw? It is hard enough for an adult, too. And 19 every time the icy solution (溶液) touched her lips, you could see the 20 in her eyes. I learned that you can't hurry a child through a milkshake.