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- Unlike a similar shelf cloud, a roll cloud is completely detached from their parent cumulonimbus cloud. 与一朵类似的隔板云不同，波状云与积雨云是完全分离开的。
- A roll cloud is a low, horizontal tube-shaped arcus cloud associated with a thunderstorm gust front, or sometimes a cold front. 蘑菇云层是由造成瑞利-泰勒不稳定性的地面附近大规模低密度热气体突然形成而造成的。
- Roll clouds can also be a sign of possible microburst activity.Cool air sinking air from a storm cloud’s downdraft spreads out across the surface with the leading edge called a gust front. 大规模气体急剧上升，形成狂暴的漩涡，整个漩涡向下俯冲，卷起大量烟雾和碎片并吸附在漩涡中心，从而形成蘑菇的“茎干”部分。
- A cloud is a mass of vapor in the sky. 云是天空中的水汽团。
- Chock the barrel up or else it will roll over. 用楔子塞住圆桶,不然它会滚过去。
- The rolling clouds looked beautiful in the brief moonlight.Wisps of clouds. 在淡淡的月光的照耀下，一束束的浮云显得好美。
- A cloud is a condensation of water vapour. 云是由水蒸汽凝缩而成的。
- The slow steady roll of the ship made him sick. 轮船不停地缓慢摇晃使他感到不适。
- There are several kinds of cloud formations. 云层的构成方式有好几种。
- The couple seemed to be on cloud nine. 那对夫妇看上去极其幸福。
- The sun disappeared behind a cloud. 太阳消失在一片云后面。
- The desk calculator use a roll of paper. 这台台式计算机使用卷纸。
- She is crazy about rock and roll. 她喜欢摇滚乐。
- The wind dispersed the cloud from the sky. 风吹散了天上的云。
- I'm going to a rock and roll concert tonight. 我今晚正要去参加摇滚音乐会。
- He was on cloud nine after winning the competition. 他在比赛获胜後欣喜若狂。
- The banks of dark cloud promised rain. 天上片片乌云，就要下雨了。
- At midnight the storm abated, the rolling clouds parted, and the stars glittered keenly about the sleeping camp. 午夜,风雨渐渐平息,滚滚的乌云分散开来,星星在进入睡乡的露宿地上空明亮地闪烁。
- If the table top isn't level, things will roll off. 如果桌面不平，东西就会滚下来。
- The boy turned up missing at roll call. 小男孩在点名时不见了。
