— Can I use the telephone on the table, sir?

一 Under no circumstances ____to use the telephone in the office for personal affairs.

A．anyone is allowed

B．nobody is allowed

C．is anyone allowed

D．is nobody allowed

25℃时，将pH=a的CH₃COOH溶液V_amL与pH=12的NaOH溶液V_bmL混合．下列说法正确的是（　　）

A．若V_a=V_b，且NaOH与CH₃COOH恰好完全反应，则a＞2

B．若a=2，混合后溶液pH=7，则混合后V总＞2V_b

C．若a=2，混合后溶液pH＜7，则Va一定大于V_b

D．若V_a=V_b，a=2，混合液中微粒浓度关系为：c（Na⁺）＞c（CH₃COO^-）＞c（OH^-）＞c（H⁺）