能在溶液中大量共存的一组离子是 [ ]

A．NH₄⁺、Ag⁺、PO₄^3-、Cl^-

B．Fe³⁺、H⁺、I^-、HCO₃^-

C．K⁺、Na⁺、NO₃^-、MnO₄^-

D．Al³⁺、Mg²⁺、SO₄^2-、CO₃^2-

— Could you please tell us about some good ways to learn English?

— My suggestion is that reading often and writing regularly ________. [ ]

A. are needed

B. is needed    

C. be needed  

D. should need