_______ the difficulty that he has supporting his big family, he still makes every effort to realize his dream, which I believe is __________ his reach.

A．Despite; within

B．Though; beyond

C．Though; within

D．Despite; of

男，5l岁。重症肺炎患者，入院后次日病情加重，突发持续性呼吸急促，发绀，伴烦躁，呼吸频率38次/分，心率108次／分，律齐，两肺可闻及湿哕音。血气分析：pH7.34，PaO2 50mmHg，PaCO2 30mmHg。胸片示两中下肺纹理增多模糊，斑片状阴影，心胸比例正常。

为缓解病人的呼吸困难，最好采用

A．高频通气

B．持续气道正压通气(CAPA)

C．呼气末正压通气(PEEP)

D．高浓度吸氧

E．双气道正压通气(Bi—PAP)