情态动词后为什么加现在完成时?who could never have imagined.

问题描述:

情态动词后为什么加现在完成时?who could never have imagined.
1.Fredierick William I,the king of prussia,who could never have imagined that his greatest gift to the russian people would have such an amazing history.
——————这一句中,为什么会出现could+现在完成时的结构,为什么要这么用?
2.另一个问题,The design of the room was in the fancy style popular in those days.
这个句子中popular充当什么成分,难道充当style的定语?它不是形容词吗?这是什么用法?
ps:例句都是英语课本上的,无误.
轩...2已经明白了。
(1)中,是说威廉在过去不会想到,完全可以用对过去的陈述语气啊,为什么用虚拟?

1.是虚拟语气2.popular是表语,句子中主语是The design of the room 动词是was,in the fancy style是插入语,其实它也可放在句子的最后,或者去掉也不会影响句子的主要意思.所以句子简化后,就是The design of the room ...