大坝出现塌方.A section of the dam has caved in.他们的房子在一次塌方中被掩埋。Their house was buried by a landslide.风暴致使萨沃纳发生塌方和洪灾。The storm caused landslides and flooding in Savona....
The birds cannot afford to relax their vigilance against predators.鸟儿不敢放松对捕食者的警戒。Constant vigilance is necessary in order to avoid accidents.为了避免意外事故,必须经常保持警惕.Never relax your vigilance while you live in peace.你们要居安思危.We...