呼吸性酸中毒可由下列哪种情况引起（）.
A.发热
B.贫血
C.肺气肿
D.癔病
E.哮喘
参考答案：C
解析：呼吸性酸中毒可由肺气肿引起。
He spent as much time as he could ______ his spoken English. [ ]
A. improve
B. improving
C. to improve
D. improved
对小儿心肺复苏，胸外心脏按压部位为（）
A.左侧第5肋间腋前线交点
B.心尖部
C.胸骨下段
D.胸骨中段
E.胸骨中点
