口对口人工呼吸法即使操作正确,吸入氧浓度也常低于()
A.21%
B.18%
C.15%
D.12%
E.10%
参考答案:B
股骨下1/3骨折,易造成()。
A.股动脉损伤
B.腘动脉损伤
C.皮神经损伤
D.肱静脉损伤
E.坐骨神经损伤
21. He apologized ________ late.
A.to his teacher to arrive
B.to his teacher for arriving
C.at his teacher to arrive
D.at his teacher for arriving