A:Mg2+、H+、NO3﹣
B:Mg2+、Fe3+、H+、NO3﹣
C:Fe3+、H+、NO3﹣
D:Cu2+、H+、NO3﹣
现代火箭用液态氢作燃料,是因为它具有( )
When playing football, Tom had his leg b____and was sent to a hospital.
已知函数fx=x3+3mx2+nx+m2在x=-1时有极值为0,则m+n=( )