The medieval town was fortified with a high wall and a deep moat.这座中世纪的城市用高墙深沟来加强防御.A fire on the city gate brings disaster to the fish in the moat.城门失火，殃及池鱼。Boys in the boat bought buoys in the moat.船里的男孩买了护城河里的浮筒.The c...
It's quite important to gain the ability to cope successfully with corrosive atmospheres and particles.很重要的是获得能够成功地克服气体和粒子腐蚀的能力.The generation of aerosols in polluted atmospheres has been investigated in several exp...