常见金属活动性顺序如图4:下列各组物质间能发生反应的是
A:铜和硝酸钠溶液
B:铁和稀盐酸
C:锌和氯化钾溶液
D:银和稀硫酸
When playing football, Tom had his leg b____and was sent to a hospital.
已知全集为R,集合A=x|12x≤1,B=x|x2-6x+8≤0,则A∩CRB=( )
辛亥革命后,孙中山进行了反对北洋军阀的斗争,其核心目标是()