耳门位于()。丝竹穴位于()。
参考答案:耳屏上切迹的前方,下颌骨髁状突后缘;眉梢处
— Air quality in our city is becoming worse and worse.
—Yes. These days' PM2.5 readings are frightening. We must do something to ______air pollution.
A.reduce
B.remove
C.collect
D.gather
简述厌氧生物处理的三个阶段及产物。