血中Hb含量低于多少时,即使重度缺氧,亦难发现发绀
A.<50g/L
B.<60g/L
C.<70g/L
D.<80g/L
E.<90g/L
参考答案:B
_____ , I think, and the problem could be settled.
A.If you make your efforts
B.So long as you keep your spirits
C.A bit more efforts
D.making great efforts
煤矿发生事故后,( )煤矿事故调查工作,拒绝接受调查取证、提供有关情况和资料的,由煤矿安全监察机构给予警告,可以并处3万元以上15万元以下的罚款。
A.不积极开展B.阻碍、干涉C.逃避D.掩盖