/,kɒnsn'treɪʃn; ,kɑnsn`treʃən/
n
1 [U] ~ (on sth) (power of) concentrating (on sth) 集中（于某事物）（之力）
*Stress and tiredness often result in a lack of concentration. 紧张和疲劳常使人精神不集中.
* a book that requires great concentration 需全神贯注才能看懂的书
* I found it hard to keep my concentration with such a noise going on. 吵闹声不绝于耳, 我很难保持精神集中.
2 [C] ~ (of sth) grouping of people or things 人或事物的聚集、集中或集合
*concentrations of enemy troops, industrial buildings 敌军、工业建筑物的集中.

n
[U]
the ability to think about something carefully or for a long time
→concentrate
　She needed all her powers of concentration to stop herself from slipping on the icy road.
　Lack of concentration was a real problem.
　I lost my concentration and fell asleep.
[U]
a process in which you put a lot of attention, energy etc into a particular activity
→concentrateconcentration on (doing) sth
　concentration on your health
　concentration on providing quality value and service
[U and C]
a large amount of something in a particular place or among particular people
→concentrateconcentration of
　the concentration of greenhouse gases in the atmosphere
　the concentration of power in the hands of a few
　the effect on trees of high concentrations of sulphur dioxide around industrial areas
　people with blood alcohol concentrations above the limit
[C]technical
the amount of a substance contained in a liquid
→concentrate
high/low concentrations
　Additives are expensive but are used in very low concentrations.
concentration of
　allowable concentrations of pesticides in drinking water