Englishfor English speakers
concentration
Noun
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A concentration is a large amount of something in one place or group.
The oil-sands in Alberta, Canada, contain high concentrations of oil.
The growing concentration of people in cities is causing new problems.
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Concentration is the ability to focus your attention on something.
Runners mustn't worry or do anything else to break their concentration.
A clean desk in a quiet place will help students improve concentration.
The government's concentration should be on helping those in the greatest need.
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The amount of solute in a solution; the concentration of a solution is measured in parts per million (ppm)
cell
Noun
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A cell is a room in a jail where prisoners are kept.
He was arrested and kept in a small cell for one day.
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A cell is a unit of a living organism.
A plant cell has a cell wall.