focus one's attention or mental effort on a particular object or activity.
she couldn't concentrate on the movie
同义词：
focusdirectcentercentralizebring to bearhome in onzero in onfocus one's attention onfocus onpay attention tokeep one's mind onapply oneself toaddress oneself todevote oneself toget down toput one's mind tobe absorbed inbe engrossed inbe immersed inthink about closelyconsider closelyrack one's brains about/overcudgel one's brains about/overinformal：get stuck into
2
gather (people or things) together in numbers or in a mass.
wealth was concentrated in the hands of the governing elite
3
increase the strength or proportion of (a substance or solution) by removing or reducing the water or any other diluting agent or by selective accumulation of atoms or molecules.
plants and microorganisms can concentrate metals from the environment
