E.g. the sky is full of forbidding thunderclouds .
天空布满了令人生畏的雷雨云。
Lenticular clouds can also be caused by other speed bumps , such as tall thunderclouds , but because they often form on the downwind sides of mountains , they are also known as lee clouds , wave clouds or lee wave clouds .
During the sultry afternoons , we took refuge by the fan-shaped pool , gazing at the thunderclouds rolling in with only the rasping of cicadas interrupting the silence .
