cloud在什么情况下是可数名词,在什么情况下又不可数?

ls的就把辞典里的ctrl+c有点不厚道啊。

cloud通常作云是可数名词
唯有表示空中的群体，遮暗物，烟尘，阴影 的时候做不可数
例子就比如楼上说的蝗虫，或者空气中的尘埃等等。
通常都是可数。a piece of cloud一朵云covered with clouds被云覆盖
此外cloud还可以作使动用法表示使布满云彩使遮暗等等。

回答完毕。

cloud: [ klaud ]

n. 云,忧色,云状的烟
v. 以云遮敝,笼罩

词形变化:
形容词:cloudless 动词过去式:clouded 过去分词:clouded 现在分词:clouding 第三人称单数:clouds

例句与用法:
1. The sad news of her father's death was the only cloud on an otherwise happy year.
她父亲的死讯是她愉快的一年中唯一伤心的事。

2. When there are black clouds you can tell it's going to rain.
有乌云的时候，就知道快下雨了。

3. The thick mist clouded the mountain-top.
浓雾笼罩着山顶。

英英解释:
名词cloud:

1. any collection of particles (e.g., smoke or dust) or gases that is visible

2. a visible mass of water or ice particles suspended at a considerable altitude

3. out of touch with reality

4. a cause of worry or gloom or trouble

5. suspicion affecting your reputation

6. a group of many insects
同义词：swarm

动词cloud:

1. make overcast or cloudy
同义词：overcast

2. make less visible or unclear
同义词：obscure, befog, becloud, obnubilate, haze over, fog, mist

3. billow up in the form of a cloud

4. make gloomy or depressed

5. place under suspicion or cast doubt upon
同义词：defile, sully, corrupt, taint

6. colour with streaks or blotches of different shades
同义词：mottle, dapple

7. make milky or dull

1. 云[C][U]
The sky became suddenly covered with dark clouds.
天空突然变得乌云密布。
2. (尘埃、烟等)云状物[C][(+of)]
3. (移动中的昆虫、鸟等的)一大群[C][(+of)]
A cloud of locusts hit the farm.
大群蝗虫袭击了那个农场。
4. 阴影;阴云[C]
5. (大理石等的)黑斑[C]

[C]可数
[U]不可数