particle cloud

例句：

1. 1. The particlecloud was so dense that it blocked outthe sun.
   颗粒云非常密集，以至于挡住了太阳。
2. 2. The scientist observed the particlecloud and recorded its properties.
   科学家观察了颗粒云并记录了其性质。
3. 3. Theparticle cloud was a sign of an approachingstorm.
   颗粒云预示着一场即将到来的暴风雨。