下列各组离子在溶液中能大量共存的是( )

A．NH₄⁺ SO₄^2- NO₃^- 　　　　

B．Ba²⁺ SO₄^2- NO₃^-

C．Na⁺ H⁺ CO₃^2-　　　　

D．Cu²⁺ OH^- Cl^-

It's very important _____ him _____ the violin very well. [ ]

A. of, to play

B. for, to play

C. of, plays

D. for, plays