water barrier短语¹³¹⁶²⁰⁺³ 基本例句 防水层 They had expected that the Germans would fight only a delaying action and, conserving their strength, retire behind the formidable water barrier of the wide and swift- flowing river. 他们预计德国军队只能采取拖延战术，而且为了保持实力，会退到河面辽阔、水流甚急、极难强渡的天堑的后面去。 jukuu