下列各组离子在溶液中能大量共存，通入CO₂后仍能大量共存的一组是 [ ]

A．K^＋、Ca^2＋、Cl^－、NO₃^－

B．K^＋、Na^＋、Br^－、SiO₃^2－

C．H^＋、Fe^2＋、SO₄^2－、Cl₂ 

D．K^＋、Ag^＋、NH₃·H₂O、NO₃^－

Buying clothes      a hard job because the clothes a person likes         not very often fit him or her.

A．are: do

B．is; does

C．are; does

D．is; do