dìng / qī / gēng / huàn / lǜ / shā / kě / yǐ / tí / gāo / zhè / tào / jìng / shuǐ / xì / tǒng / de / guò / lǜ / xiào / guǒ

定期更换滤砂，可以提高这套净水系统的过滤效果。

Replacing the filter sand regularly can improve the filtration efficiency of this water-purification system.