dì xià shuǐ / zhōng / hán yǒu / dà liàng / de / zhòng tàn suān gài / suǒ yǐ / yìng dù / jiào gāo

地下水中含有大量的重碳酸钙，所以硬度较高。

Groundwater contains a large amount of calcium bicarbonate, so its hardness is relatively high.