airhop空中旅行airn.空气；天空；空中；感觉；神态；曲调；装腔作势v.晾干；使通风；广播air charge rate换气速率air impingement气体射流冲击air line filter风管过滤器air-atomizing气力喷雾air portability空运轻便性air traffic hub航空交通枢组air-flow rate通风量air silde valve空气分配阀air thermometer空气温度计,空气温度表air-agitation气体搅动

1. Oxygen and carbon dioxide from the air enter through the stoma.
   氧和二氧化碳从空气中进入气孔。
2. Each stoma is surrounded by two crescent-shaped GUARD CELLS, attached to each other at their ends, which regulate the opening and closing of the pore by changes in their turgidity.
   每个气孔被两个新月形的保卫细胞头尾相接围绕而成。