constantly 侧重于事件发生的稳定性和持续性以及经久不变的状态
The direction of the wind is constantly changing. 风向不断变化. We are constantly being reminded to cut down our fat intake. 不断有人提醒我们要减少脂肪的摄入量.
continually 侧重一段时间内多次发、时断时续或中断时间很短而又接连发生的状态
Malcolm was continually changing hismind. 马尔科姆不断地改主意. I had been writing him continually, trying to get him to call me. 我一直在给他写信,想让他给我打电话.
continuously 侧重在时间、物质或广度上没有间断的
The civil war has raged almost continuously since 1976. 自从1976年开始,内战几乎没有中断过. It is the oldest continuously inhabitedcity in America. 这是美国最古老的一直有人居住的城市.
ceaselessly 侧重指令人不快的事不停歇或无休止出现的状态
The wounded man moaned ceaselessly. 那个伤员呻吟不止. His eyes, seeing nothing, moved ceaselessly about the room. 他的眼睛现而不见,可是不停地向屋子里四面看.