爱米利的米粒
Have you ever seen tall, dark puffy clouds forming on a hot humid afternoon? These are called cumulonimbus clouds, sometimes nicknamed "thunderheads." They can actually form any time of day when the temperature falls rapidly higher up in the sky. These tall dark clouds are full of moisture and contain strong up and down air currents. Cumulonimbus clouds may tower more than 50,000 feet, and cover from just a few square miles up to two hundred square miles. When a lightning bolt flashes through the sky we see it instantly. The following thunder, the sound of the lightning, takes a few seconds longer to reach us, as light travels much faster than sound. Thunder never just goes "Boom!" and then stops, rather one hears a loud clap followed by several seconds of rumble. What is Lightning? To put it simply, lightning is electricity. It forms in the strong up-and-down air currents inside tall dark cumulonimbus clouds as water droplets, hail, and ice crystals collide with one another. Scientists believe that these collisions build up charges of electricity in a cloud. The positive and negative electrical charges in the cloud separate from one another, the negative charges dropping to the lower part of the cloud and the positive charges staying in the middle and upper parts. Positive electrical charges also build upon the ground below. When the difference in the charges becomes large enough, a flow of electricity moves from the cloud down to the ground or from one part of the cloud to another, or from one cloud to another cloud. In typical lightning these are down-flowing negative charges, and when the positive charges on the ground leap upward to meet them, the jagged downward path of the negative charges suddenly lights up with a brilliant flash of light. Because of this, our eyes fool us into thinking that the lightning bolt shoots down from the cloud, when in fact the lightning travels up from the ground. In some cases, positive charges come to the ground from severe thunderstorms or from the anvil at the very top of a thunderstorm cloud. The whole process takes less than a millionth of a second. 不知道你需要多长的，希望这个能帮助你。中文可能不是翻译的很好，只能当参考。你在炎热潮湿的下午见过高大，黝黑蓬松云彩形成吗？这些被称为积雨云，有时绰号“thunderheads”。其实，他们是当天空的气温急速下降的时候形成。这些高大的乌云含有的充分的水分和强大的上升和下降气流。积雨云堆起来可以超过50,000平方英尺，面积从几平方英里到200平方英里。当闪电在天空闪烁，我们可以即刻看到它。而接着的雷声，还登上需要几秒钟。这是因为光的速度远远快于声音。雷从来不只“轰！”一声，然后停止，而是听到一个响亮的轰声后，还接着有几秒的隆隆声。 什么是闪电？ 简单来说，闪电就是电。它在形成的上升和下降的积雨云中间，水珠，冰雹，冰晶相互碰撞的结果。科学家认为，这些碰撞产生了离正电和负电荷，负电荷下降到云的底部，而离正电则停留在云的中上游部分。当然，地面上也有离正电的产生。当这个电极的差异达到一定程度，云便会向地面放电，或者上游的云会对下游放电，或者云朵间也会放电。这些都是典型向下流动负电荷的闪电，但是地面的正电荷也会向上跳跃，这产生了锯齿状的负电荷向下路径突然亮起了光灿烂闪光。正因为如此，我们的眼睛被欺骗了，以为闪电是从云上下来的，而闪电从地面向上升。因为这整个过程只需时超过百万分之一秒的少。
叮叮猫儿要飞
Cirrus: like a feather like silk yarn, silk thread to float, the highest, the thin, clear symbol.Cirrocumulus: like the scale-like ripple, in rows of cirrus, very tall, very thin, no rain.Cumulus: like cotton, morning, evening dissipated, about 2000 meters, thin, moderate sunlight.Altocumulus: like prairie white sheep, compressed globose, neatly arranged, about 2000 meters, thin, fine.Cirrostratus cloud: cirrus aggregation, forward, like a white silk screen over the sky, the high, clear to overcast.High level cloud: cirrus is getting more and more thick, like frosted glass covered the sun, low, it will rain snow.Nimbostratus Altostratus: become more thick, dark grey sky clouds clouds, rain and snow is lower, continuous.Cumulonimbus clouds: cumulus quickly form a tall mountain, overcast sky, lower, hail storm.卷云：像羽毛像绫纱，丝丝缕缕地漂浮着，最高、最薄，象征晴朗。卷积云：像水面的鳞波，是成群成行的卷云，很高、很薄，无雨雪。积云：像棉花团，上午出现，傍晚消散，2 000米左右，较薄，阳光温和。高积云：像草原上雪白的羊群，扁球状，排列整齐，2 000米左右，较薄，天晴。卷层云：卷云聚集，向前推进，像白绸幕蒙住天空，高，晴转阴。高层云：卷云越变越厚，像毛玻璃遮着太阳，低，将下雨雪。雨层云：高层云变得更厚，暗灰色云块密布天空，更低，雨雪连绵。积雨云：积云迅速形成高大云山，乌云密布天空，更低，雷雨冰雹。
