属于物理性因素的是()
A.过度吸烟与饮酒
B.残根、残冠和不良修复体
C.EB病毒
D.多种维生素缺乏
E.癌基因被激活或抗癌基因被抑制关于肿瘤的致病因素
参考答案:B
因式分解:x2y-4y= ◆ .
How many Americans include yoga in their fitness regiment().
A. 5,000,000
B. 15,000,000
C. 50,000,000
D. 150,000,000