皮肤黏膜出现发绀时,毛细血管血液还原血红蛋白至少超过().
A.75g/L
B.50g/L
C.100g/L
D.45g/L
E.30g/L
参考答案:B
安全阀的弹簧压得太紧造成安全阀起压不开启故障的排除方法是()。
A、重新调整螺丝
B、更换弹簧
C、调整阀杆
D、调整阀芯
The length of the steering oar in a lifeboat is().
A.shorter than the rowing oars
B.the same length as the rowing oars
C.longer than the rowing oars
D.unrelated to the length of the rowing oars