—She couldn't have done that sort of thing.

—Whatever she did was reasonable, _____ to what you did.Besides,it's none of your business.Get

down to _____ your lessons.[ ]

A. comparing; doing  

B. comparing; do

C. compared; doing  

D. compared; do

下列离子在溶液中可以大量共存的一组是（　　）

A．NH₄⁺、K⁺、OH^-

B．H⁺、SO₄^2-、Cl^-

C．Na⁺、H⁺、HCO₃^-

D．Ca²⁺、NO₃^-、CO₃^2-