thundercloud

1.a bank of thunderclouds;

一堆云；

2.thunderclouds that promise rain.

有云就会有雨

3.thunderclouds of impending war.

迫在眉争云

4.that the electric charge would try to find the most direct route between thundercloud and ground.

因为我们认为它会在雨云和地面之间找到最直路线。