卡介苗是牛型结核分枝杆菌发生下列哪种变异后的产物()
A．毒力变异
B．耐药性变异
C．形态结构变异
D．抗原性变异
E．菌落变异
参考答案：A
根据对话内容排序：小题1:______小题2: _____ 小题3: _____ 小题4: _____ 小题5: ______
A．Anything else?
B．Yes. I would like to have the beef, please.
C．OK. I will get the things ready for you soon.
D．May I take your order, sir?E. A tomato salad and a bottle of beer.
对岩石斜坡，下列（）种情况对斜坡稳定性最不利。
A．岩层倾向与斜坡同向，倾角大于45°且大于斜坡坡度
B．岩层倾向与斜坡同向，倾角大于45°且小于斜坡坡度
C．岩层倾向与斜坡同向，两者倾角相等
D．岩层倾向与斜坡逆向，倾角大于45°，斜坡较陡
