During the reading lesson, the teacher asked students to read a few ______ from the novel.

A．pieces

B．essays

C．fragments

D．confirms

成人呼吸窘迫综合征的最重要的诊断依据是()

A．呼吸频率增加，大于28次/min

B．肺泡气—动脉血氧分压差降低

C．氧合指数小于300

D．肺内分流量减少

E．血气分析显示为低氧伴轻度二氧化碳潴留