They load a rocket and launch it into the belly of a thundercloud.

他们装载火箭，把它发射到雷雨中。

The thundercloud had so darkened the room that she could not very clearly see what was in it.

雷雨让屋子变得暗，她看不清楚里面的东西。

It was believed until not long ago that lightning from a thundercloud always moves down heading in the direction of the earth.

直到不久以前，人们还相信雷雨产生的闪电总是朝着地球的方向向下移动。

According to the U.S. National Weather Service, tornadoes form from thunderclouds and can reach swirling speeds in excess of 600 kilometers per hour.

根据美气象局的资料，龙卷风是由雷雨所形成，旋转速度每小时可高达600公里以上。

To make matters worse, Gobber was standing on the harbor wall watching them come in, arms folded, brows as low as Thor's thunderclouds.

更糟糕的是，戈伯站在港口围墙上看着他们进来，双臂交叉，眉毛低如雷神的雷雨。

The altitudes where lightning is born are limited by the height of a thundercloud, the direct source of lightning which is 20 kilometers or 12.4 miles at its highest.

闪电产生的高度受到雷雨高度的限制，雷雨的直接来源最高为 20 公里（12.4 英里）。