缺铁性贫血实验室检查最灵敏指标是()
A.血清铁蛋白降低
B.血清铁降低
C.红细胞原卟啉含量增高
D.总铁结合力增高
E.红细胞中央淡染区扩大
参考答案:A
If it hadn’t been for the help of my English teacher, I the first prize in the English Writing Competition.
A.would not win
B.would not have won
C.would win
D.would have won
巷道支承压力是由于()。
A、开掘巷道后自然形成的
B、支护引起的
C、岩体内固有的