下列各组离子在pH=14的溶液中能大量共存的是
已知函数f(x)= ax-3x+1 (a∈R).
—Sorry,sir.But it is the management rules of our hotel that payment _____ be made in cash.
如图所示,A,B,C,D为我国四大地理区域,a、b、c为四大地理区域的三条界线。