新概念2个动词的句子

题目

新概念2个动词的句子
新概念2 的82课句子
it is now known that many of these monsters which have at times been sighted are simply strange fish.
这句 which have at times been sighted are simply strange fish.为什么还加are?前面是被动语态我懂后面加的are看不懂.
Though people have often laughed at stories told by seamen
这句told前面不用加什么词吗?和laughed at 动词重复了啊?

答案

It is now known that many of these monsters,which have at times been sighted,are simply strange fish.
which have at times been sighted是用来修饰monsters的.