In many areas “atoll” clouds (clouds of vertical development) are produced over small islands. These are the result of（）.
1、Cumulonimbus clouds are formed by（）.
Cumulonimbus clouds are formed by（）.Avertical air movementsBheavy rainstormsChorizontal air movementsDany movement of moist air
昙点（cloud point）
3、Clouds with the prefix “nimbo” in thei
Clouds with the prefix “nimbo” in their name（）.Aare sheet or layer cloudsBhave undergone great vertical developmentCare middle or high altitude cloudsDare rain cloud
4、（）is a silvery cloud in the front of f
（）is a silvery cloud in the front of feathers or fibres seen high up against a blue sky.ACirrostratusBCirrusCCirrocmulusDAltostratu
5、Cirrus clouds are composed primarily o
Cirrus clouds are composed primarily of（）.Aice crystalsBwater dropletsCsnow crystalsDnitroge
6、Clouds appearing in the following orde
Clouds appearing in the following order: cirrus，cirrostratus，altostratus，stratus，and nimbostratus usually indicate the approach of a(n)（）.Awarm frontBoccluded frontCmedium frontDcold front