In spring in Guangzhou, whenever the weather in the south warms up, the walls and floors of the classroom are very wet, or even "no water". (1) Apply what you have learned.

1) Warm days usually occur when the weather is sultry and the air humidity is high (the air contains more water vapor). Hot steam meets cold floor tiles, walls and blackboards, giving off heat and liquefying it into water.

(2) If there is air conditioning in the classroom, you can close the doors and windows and get wet; If there is no air conditioning in the classroom, try to open fewer doors and windows, and some newspapers can be spread on the ground and walls;