—I don't imagine Russ and his poor dog had a good time on

　the deserted island，________？

—I have no idea.

A．didn't they

B．do you

C．did they

D．hadn't they

炉墙是管式加热炉的重要组成部分，其结构主要有砖结构、耐热混凝土结构和（）。