cloud condensation nuclei

例句：

1. 1. The formation of cloud condensation nuclei is crucial for the formation of clouds.
   云凝结核的形成对于云的形成至关重要。
2. 2. The presence of cloud condensation nuclei can affect the amount of precipitation in a region.
   云凝结核的存在可以影响一个地区的降水量。
3. 3. Researchers have been studying the behavior of cloud condensation nuclei in order to better understand the formation ofclouds.
   研究人员一直在研究云凝结核的行为，以更好地理解云的形成。