改句1：The Titanic was considered as unsinkable.
considered as 不对
正确的说法是 considered to be
改句2：对
改句3：The Titanic was thought to be as unsinkable.
thought to be as 要除去 as
The Titanic was thought to be unsinkable.
改句4：对
希望帮到了你,
我是加拿大人,前海外英语老师.
英语提问：以下句子改写得对吗,帮我看看,有问题请指正,