Even if a piped water supply is safe at its source , it is not always safe by the time it reaches the tap 即使管道供水系統(tǒng)在水源處安全的,等水到達(dá)龍頭時(shí)就不一定總是安全的了。
Mosquitoes , and flies that live near in water bring yellow fever , malaria and sleeping sickness , so good piped water supplies are needed to reduce the need for people to gather in such an area 因此,為了減少人們聚居在具有傳染源的水域附近,良好的管道供水系統(tǒng)必不可少。 )