阅读下文，从各小题所给的四个选项中选出能回答所提问题或完成所给句子的最佳答案。
Nick is a 14-year-old school boy. His life is full of exams and he studies on weekdays. He has little
free time. He thinks playing computer games is the best way to make him relax. When he has free time,
he sits in front of the computer. Just like that way, he neither eats nor drinks for several hours.
Last weekend, he played games on the computer again. He was too excited and didn't want to move.
He didn't have anything for six hours. When he had to go to the bathroom, he found he could not move.
He was taken to the hospital. The doctor told him he should do some, more different kinds of activities.
In other words, he needs more exercise and outdoor activities to make him have a healthy body.
After coming back from the hospital, Nick follows the doctor's advice. He often plays soccer with his
friends. Sometimes he still plays computer games on weekends, but he never does it for long. Now, he
lives a happy and healthy life.
1. How old is Nick?
A. 13.
B. 14.
C. 15.
D. 16.
2. Nick likes _____ in his free time.
A. riding a bike
B. playing the guitar
C. playing computer games
D. having a school trip
3. Who took Nick to the hospital?
A. His dad.
B. His mom.
C. His neighbor.
D. We are not sure.
4. Why was Nick taken to the hospital?
A. Because he was too excited.
B. Because he had a cold in the morning.
C. Because he was too nervous of his studies.
D. Because he couldn't move after playing computer games so long.
5. Nick should _____ to follow the doctor's advice.
A. go to a movie
B. listen to music
C. take more exercise
D. p]ay computer games
之间区域内存在着相互垂直的匀强电场和匀强磁场，一带电粒子（不计重力）以初速度v0由A点垂直于MN进入这个区域，带电粒子沿直线运动，并从C点离开场区。如果撤去磁场，该粒子将从B点离开场区；如果撤去电场，该粒子将从D点离开场区。则下列判断正确的是（ ）
