云界

例句：

1. 1. The clouds were so thick that they obscured the sun's rays.
   云层非常厚，遮住了阳光。
2. 2. The sky is a vast expanse of blue, where the clouds dance and play.
   天空是一片广阔的蓝色，云朵在其中翩翩起舞。
3. 3. The clouds above us are moving in a slow, steady pattern.
   我们上方的云层正在缓慢而稳定地移动。