【成语来源】
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。
【文化链接】
大家是不是一直对“be concentrated on sth”和“be concentrating on sth”感到有些迷惑呢？今天就有我来给大家讲解一下吧~
我们先来看一段话：
The teacher wrote two sentences on the whiteboard and asked us what‘s the difference.“He is very concentrated on…” and “He is very concentrating on”
老师在白板上写下两句话，让我们说出区别，这两句句子是“He is very concentrated on…”和“He is very concentrating on”
A girl sits besides me said it was very similar as the way “surprised” and “surprising” is used.
做在我身边的女孩说这两句句子的区别就是“surprised”和 “surprising” 的区别类似。
He is surprised means he is surprised by something.He is surprising means he himself is something surprising.
“He is surprised”意思就是“他感到很惊喜”，而“He is surprising”意思则是“他总是让别人感到很惊喜。”
“Good，” the teacher says，“Concentrated means something with high density， like concentrated jam and orange juice.If you want to say the person is focusing on something mentally you should use ‘He is concentrating on…‘”.
“非常好，”老师说，“Concentrated就是说某样东西密度很高，浓度很大，就像是果酱、橘子汁”，但如果你想说某人专心致志做某事就是“He is concentrating on…”.
Oh…… my goodness， I must have been saying he is concentrated on … for decades now.
哦，我的天啊，我至少说“he is concentrated on……”有十年时间了…