– Have you moved in the new house?

– Not yet, the rooms ____.

A．are being painted

B．are painting

C．are painted

D．are being painting

某酒店的一个大厅里，为了使客人感觉厅内宽敞明亮，主人在迎面墙上装了一面与墙等大的平面镜，这里利用了________原理达到这一目的的，这样使人感觉房间大小是原来的________倍。