—What do you want those old boxes?

—To put things in when I move to the new flat．

A．by

B．for

C．of

D．with

在常温下，pH = 9的NaOH溶液和CH₃COONa两种溶液中，假设由水电离产生的OH^─离子浓度分别为a和b，则a与b的关系为

A．a>b

B．a=10^-4b

C．b =10^-4 a

D．a =b