在pH=1的溶液中能大量共存的一组离子或分子是[ ]

A．Na⁺、Mg²⁺、ClO^-、NO₃^-

B．Al³⁺、 NH₄⁺、 Br^-、Cl^-

C．K⁺、Cr₂O₇^2-、CH₃CHO、SO₄^2-

D．Na⁺、K⁺、SiO₃^2-、Cl^-

So involved with computers ____ that the leaders at the summer computer camps often had to force them to break for sports.

A．has the children become

B．did the children become

C．has become the children

D．became the children