Sushi, a famous man of letter in Northern Song Dynasty, used to write in Answer to Wang Qi Again that :"the content of books is as rich as that of the sea with everything concluded. On the contrary, people's energy is so limited that it can't reach every aspect. Thus people can only choose one of the intertests to learn and a scholar can only be an expert of one field." Likewise, Max also revealed that:" People can't ride two horse at a time. Once he makes a choice, he need to give up the other. A wise man can dispose of distractions and be concentrated on only one field until learn it well." Thoughout history, nearly no great man or scientist gained breakthough in a certain field without concentration. Take Fabre for an example. To observe the habits of insects, he usually ignores everything else. One day ,he crouched down on a big stone early in the morning. Some village women saw him when they started to pick grapes in the morning until they got back in the dusk. They couldn't understand and said: " Fabre must be mad that he spares the whole day watching a stone. " In fact, Fabre spent numerous days and nights to observe habits of insects. Any task can be fulfilled under such persistence. And the latest gospel of the world is to learn your aim and to try to finish it. This sentence is believed to lead you to success.