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　　floodwaters

　　英：

　　美：

　　retract和retreat的用法有什么区别呀？

　　retract v. 收回，撤销（已说的话或已答应的事） He retracted his words.

　　使缩回，使缩入 The sea otter can retract the claws on his front feet.

　　retreat v.n 撤退 （军队）；后退；离开；范围缩小 例 The flood waters are slowly retreating.撤回计划，多用于书面表达，股价下跌

　　water waters 论不可数名词加s的意义

　　当不可数名词表示具体案例时，则“可数名词化”。如a knowledge of history, a fire, 3 coffees