烧伤患者长时间深静脉置管，可引起（）
A.静脉血栓
B.化脓性静脉炎
C.动静脉瘘
D.皮肤坏死
参考答案：A, B
"Genius" is a complicated concept, _ _ many different factors. [ ]
A. involved
B. involving
C. to involve
D. being involved
铝电解生产过程中阳极气体主要成分为（）和（）的混合物。
