★ 表示洪水时可数.加了-s肯定算复数.★ 表示洪灾、洪水泛滥时,应该不可数.有个表泛滥义的习语：in flood.《牛津高阶英汉双解词典》例句：☆ The heavy rain caused floods in the houses by the river.这场大雨下得...