The last time we had great fun was _____ we were visiting the Water Park. [ ]

A. where

B. how

C. when

D. why

若SQL语句中的ORDER BY短语中指定了多个字段，则

A) 无法排序
B) 只按第一个字段排序
C) 按自左至右的字段顺序排序
D) 按自右至左的字段顺序排序