Zhang lao shi, evapotranspiration is part of the water cycle. See wikipedia.

"Evapotranspiration is water transpired from plants and evaporated from the soil."
http://en.wikipedia.org/wiki/Water_cycle

谢谢了。
水分循环大家都早就知道。它可粗可细。
我这里是想突出生物水与空中水、地表水、地下水的四水对等地位。