Jenny was sad over the loss of the photos she shot in Canada, _________ this was a memory she especially treasured.

A．if

B．when

C．as

D．where

辩证唯物主义认识论与旧唯物主义认识论的两大根本区别表现在是否承认 ( )

A．唯物主义一元论

B．唯物主义辩证法

C．实践在认识中的地位和作用

D．唯物主义历史观