yǐ / qián / de / chéng / shì / méi / yǒu / xià / shuǐ / dào / shǐ / tǐng / shì / qīng / yùn / fèn / biàn / de / zhǔ / yào / gōng / jù

以前的城市没有下水道，屎艇是清运粪便的主要工具。

In the past, cities had no sewer systems, so excrement boats were the main tool for removing waste.