— Have you ever read The Brief History of Time?

— Yes. While in Britain, I ______ it a couple of times.

A．have read

B．read

C．had read

D．would read

某溶液中含有大量的氢离子，则该溶液不一定可以[ ]

A．与氢氧化钠溶液反应

B．与块状石灰石反应实验室制取二氧化碳

C．使紫色石蕊试液变红

D．测其PH值小于7