It is no use ____ without _____.

A．to talk, doing

B．taking, being done

C．talking, doing

D．being talked, being to do

下列各组离子能在pH=1的溶液中大量共存，且形成无色溶液的是[ ]

A．Na⁺、Ca²⁺、Cl^-、CO₃^2-

B．NH₄⁺、K⁺、NO₃^-、Cl^-

C．Na⁺、K⁺、OH^-、Cl^-

D．K⁺、Cu²⁺、SO₄^2-、NO₃^-