Daqing is located in Songnen Plain, and droughts often occur in spring. In order to alleviate the drought, artificial rainfall is often carried out, and dry ice (solid) with shells is thrown into high-altitude clouds. Dry ice enters Leng Yun and changes from solid to gas, which belongs to sublimation;

Because sublimation needs heat absorption, water vapor turns into small ice particles or small water droplets when it is cold, that is, from gas to solid ice, which belongs to sublimation; Or from gas to liquid, belonging to liquefaction.

Small ice particles become raindrops when heated, and change from solid ice to liquid water, which belongs to melting;

So the answer is: sublimation; Absorption; Ninghua; Liquefaction; Melting.