最常用于诊断颌骨恶性肿瘤的放射性核素是（）
A.131碘
B.32磷
C.35锶
D.67镓
E.99m锝
参考答案：E
It is required that all traffic participants should _____ the traffic rules to make traffic safer and faster.[ ]
A. perform
B. observe
C. support
D. possess
内部公平性原理
