下列各组中的俗称和化学名称均表示同一种物质的是

A．生石灰—氢氧化钙

B．酒精—乙醇

C．食盐—氯化钾

D．纯碱—氢氧化钠

I'd like to find some information about the Great Wall. Could you teach me ______ to search the Internet. [ ]

A. how

B. when

C. where

D. what