“Sorry” is a word that people in Britain often say in their daily life.
One day while I was w 小题1: on the street, a young man ran by hurriedly, brushing(轻擦) against my handbag. He continued his way, but turned b 小题2: and said “sorry” to me. Even in a rush, he didn’t f 小题3: to say “sorry”. One day, after I bought some bananas, the shopkeeper was passing me the change, but I wasn’t ready for it and a coin dropped onto the ground. “Sorry, Madam,” he said w 小题4: bending to pick it up. I was s 小题5: why he said “sorry” to me. Another time, I stepped on a man’s f 小题6: at the entrance to a cinema. At the same time, we b 小题7: said “sorry”.
Slowly, I got to k小题8: that when something unpleasant happens in daily life, the British don’t c 小题9: much about who is wrong. If someone is in trouble, a “sorry” is always n 小题10: . Perhaps that is w 小题11: I seldom see people quarrel on the buses or streets in Britain.
，电场宽度均为d，水平面粗糙摩擦系数为μ，一个质量为m，带正电的、电荷量为q的物体（看作质点），从第一个向右的电场区域的边缘由静止进入电场，则物体从开始运动到离开第2n个电场区域的过程中，求：