完形填空
We all admit that modern technology has taken over our lives, for good of course. Young people celebrate the fast speed 1 can move at. But there is a group of people who cannot 2.
It is the group of people who are caught up between traditional and 3 society, not exactly old and 4 change, but trying very hard to become modernized, ending up being 5in the middle. They are 40 to 60 years old and6the latest iPhone or Samsung phone. They buy an iPad just 7 they can afford to, and to play the same games on a larger screen.
They are almost 8 the teenagers five years ago, 9 on their phones playing a game or using social media. They're everywhere. And I saw something today that made me extremely 10.
On a train, a mother was 11 playing a Candy Crush-like game. Her daughter was sitting beside her. The little girl, about five years old, was talking to her mother about her day, shouting the next stop's name cheerily-obviously desperate attempts to get her mother's 12.
The mother? All she did was nod and say the occasional “mmhm”. With her eyes on the13, she concentrated on completing the level. I watched the girl make a final 14 to get her mom to look at her, and when she had 15 she sighed and fell silent, defeated.
It broke my heart, and got me 16 —what kind of game can make you 17 that you have the most beautiful thing in the world, a person you love with all your heart? What does it 18when you won't even look into her eyes or listen to her?
The scene was so familiar years ago when parents 19that their children were too interested in their mobile devices. Look how the tables have turned now. I'm 20 whether to laugh or to cry. But all I can do now is hope that this storm passes.
的带电粒子，以速度
垂直电场线方向飞入两块平行金属板间，飞出时动能为3Ek．如果这个带电粒子的初速度增加到原来的2倍，不计重力，那么该粒子飞出时动能为