1. [单选题]慢性阻塞性肺疾病失代偿期,Ⅱ型呼吸衰竭,给氧的原则是
A. 氧浓度25%~30%,氧流量1~2升/分,间断给氧
B. 氧浓度35%~40%,氧流量2~3升/分,间断给氧
C. 氧浓度35%~40%,氧流量2~3升/分,持续给氧
D. 氧浓度40%~55%,氧流量3~4升/分,持续给氧
E. 氧浓度25%~30%,氧流量1~2升/分,持续给氧
2. [单选题]
A. unlessB. when
B. since
C. although