肢端青紫症的发病因素不包括
A.衰弱
B.免疫
C.内分泌疾病
D.寒冷
E.焦虑
参考答案:B
He________an engineer by an oil company in the Middle East.
A.was employed as
B.employed as
C.was employed for
D.employed
热电阻PT100在0度时测得其阻值为:()。