血中还原血红蛋白至少达多少时,皮肤黏膜可出现发绀()。
A.>70g/L
B.>65g/L
C.>60g/L
D.>55g/L
E.>50g/L
参考答案:E
Thank you for ______ me. [ ]
A. helps
B. to help me
C. helping
锤柄松动应如何处理?