Once upon a time there was a painter who had just finished his course from a great painter. He wanted to assess his skills, so he decided to display one of his best works on a busy street.
He put his painting at a busy street-crossing. And below it a board read — "Gentlemen, I have painted this piece. Since I'm new, I might have made some mistakes in my work. 65 "
When he came back in the evening to collect his painting, he was completely shocked to see that the whole painting was filled with crosses.
66 He burst into tears and said sadly, "I'm useless and if this is what I have learned to
paint, I'm not worth teaching."
The master smiled and suggested, "My son, I will prove that you are a great artist." The master told him, "Just paint the same painting once again and give it to me."
Then they went to the same street the next morning and displayed the same painting. The master took out another board which read — "Gentleman, I have painted this piece. Since I'm new, I might have made some mistakes. I have put a box with colors and brushes just below. Please do
me a favor. 67 "The master and the young painter went back home.
They visited the place in the evening. The young painter was surprised to see that actually there was not a single correction done! 68 If you want to help people improve their behaviors, it is worth investing your effort in learning how to help people change their behaviors, attitudes and skills. Also, always remember not to get carried away or judge yourself by someone else's criticism and feel depressed as you are the best judge to judge yourself!
A．It is easy to criticize, but difficult to improve.
B．Please put a cross wherever you see a mistake.
C．Discouraged and broken, he ran to his master's place.
D．If you see a mistake, kindly pick up the brush and correct it.E. Criticizing has the function of helping people improve themselves.
，地球半径为
，地球表面的重力加速度
，地球自转周期为
，电磁波信号传播的速度约为
。卫星电话信号需要通过地球同步卫星传送，如果有两个用户在地面上用卫星电话通话，甲发出信号到乙收到信号的最短时间为 。（结果保留两位有效数字）