I couldn't concentrate, presumably because I was so tired.

我的精神集中不起来，大概是太累了吧。

《牛津词典》

Bilingual speakers often do better than monolinguals in completing certain tasks because they can concentrate better on what they are doing.

由于双语者能更好地专注于他们正在做的事情，所以他们通常比单语者在完成某些任务时做得更好。

youdao

Examinations are probably a poor instrument for measuring the quality of education because they concentrate on grades instead of abilities.

考试可能不是一个衡量教育质量的好方法，因为考试更看重成绩而不是能力。

youdao

Mr. Page, the company's chief executive, said recently that focusing on competitors can lead companies to "decay" because they concentrate on incremental improvement rather than big, risky bets that can offer a bigger payout.

WSJ: Google Follows Amazon's Lead on New Shopping Site, Delivery, Other Services

The integrated camera records a view similar to what is seen, allowing the user to share their experience with other people, and to enjoy their activities to a greater extent because they concentrate less on holding and operating the camera.

ENGADGET: Liquid Image outs Summit Series Snow Camera goggles ahead of CES

Children with the worms can't concentrate because they are scratching themselves all day and night.

CNN: With river blindness, 'you never sleep'