Doctor, I haven't been able to get enough sleep lately, and I'm too tired to concentrate in class.

医生，我最近睡眠不足，上课也很困倦，无法集中注意力。

youdao

Second, I usually have to concentrate in class listening to reason.

第二，我平时上课时都专心听讲的的缘故。

youdao

If you concentrate in class and make efficient use of your time, you will get good grades.

如果你上课专注并有效率的利用时间，你就会得到好成绩。

youdao

Home Secretary David Blunkett has already welcomed an experiment by police in Lambeth, in south London, not to prosecute in minor cases of cannabis possession in order to concentrate on tackling Class A drugs.

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