Theworldisnotonlyhun的精選

問題詳情：Theworldisnotonlyhungrybutalsothirstyforwater.Thismayseemstrangetoyou,sincenearly70%oftheearth'ssurfaceiscoveredwithwater.Butabout97%ofthatisseawaterorsaltwater.Mancanonlydrinkandusetheother3...