The China National Environmental Monitoring Center ____ air quality in urban areas from levels one to five:

excellent, fairly good, slightly polluted, poor and dangerous. [ ]

A. distributes

B. arranges

C. classifies

D. divides

慢性腹痛临床应注意以下几点，除外

A．腹痛的部位

B．腹痛的性质

C．与遗传的关系

D．腹痛与体位的关系

E．伴随症状