Be concentrating on sth 专心致志

Yi Qiu was known as the most famous expert at chess throughout the land.

奕秋是全国最有名的棋手。

Once he gave lessons on chess to two men.

有一次，他教两个人下棋。

One of them was completely absorbed in his teaching, listening attentively to Yi Qiu while the other, who seemed to be listening, had his mind on something else.

一个认真的听课，完全沉浸于其中。 另一个尽管看上去也在听课，其实在想其它的事情。

In fact, he was having a fancy that a swan was flying towards him and he had in his hands a bow and an arrow, ready to shoot.

他幻想有只天鹅正朝他飞来，而他拿着弓和箭准备把它射下来。

As a result, though he was having the same lesson together with the first man, yet he turned out a much inferior student.

所以，虽然他和另一个人上的是同样的课，他学得可差多了。

If one is not concentrating on his study, no skills will be learned.

不专心致志的学习，什么技能都学不会。