concentration ·noun (LARGE AMOUNT)
Definition: a large number or amount of something in the same place Level: C2
该地区的土壤中含有高浓度的矿物质。
The region has high ___concentrations of minerals in its soil.
严格的法律限制了工厂排放物中有害化学物质的浓度。
Strict laws limit the ___concentration of harmful chemicals in factory emissions.
春季，空气中花粉的浓度高企，导致许多人过敏。
During spring, the ___concentration of pollen in the air causes allergies for many people.