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concentration (on a task); focusing one's attention
concentration (of population, buildings, power, etc.); centralization; convergence; focus (of a debate, questions, etc.)
within a collection of works
テスト前は勉強に集中するようにしている。
I try to concentrate on studying before tests.
都市部に人口の集中が進む。
Concentration of population is progressing in urban areas.
彼女は仕事に集中して素晴らしい成果を出した。
She concentrated on her work and achieved great results.