布洛芬可以用下列哪种反应鉴别（）
A.异羟肟酸铁盐反应
B.硫色素反应
C.紫脲酸铵反应
D.重氮化偶合反应
E.维他立反应
参考答案：A
既能泻下，又能止血的药物是（）
A．大黄
B．芦荟
C．芒硝
D．牵牛子
E．番泻叶
It is clear to us that the 2012 Olympic Games _____ in London will once more draw people's attention in the
world to them. [ ]
A. having been held
B. to hold
C. to be held
D. held
