— Would you please find a world map which is drawn to a scale of _____.

— Yes, sir. Here you are.[ ]

A. one out of ten thousand

B. one in ten thousands

C. one to ten thousand

D. one of ten thousands

下述关于类风湿因子说法正确的是（）

A.在某些正常人类风湿因子可以出现低滴度阳性

B.其滴度与类风湿关节炎病情活动性、严重性无关

C.是属于：IgM型的自身抗体

D.在某些慢性感染性疾病及恶性肿瘤的患者血清中可出现阳性

E.类风湿因子阴性可以排除类风湿关节炎的诊断