1.It is said that 据说(=people say 即大家都这么说)that 后面接一个从句,that 可省略。例:It is said (that) he is only 13 years old.据说他才13岁。=He is said to be only 13 years old.他据说才13岁。其它几个的用法都是一样。2.It is thought (that)大家认为...有人...    
“it+系动词+过去分词+that从句”造句
    1.It is said that 据说(=people say 即大家都这么说)that 后面接一个从句,that 可省略。例:
It is said (that) he is only 13 years old.据说他才13岁。
=He is said to be only 13 years old.他据说才13岁。
其它几个的用法都是一样。
2.It is thought (that)大家认为......有人认为......that后同样接一个句子。例:
It is thought (that )he is the greatest person in the world.他被认为是世界上最伟大的人(同样请写出另两种表达)。
3.It is known that 众所周知......
4.It is reported  that 据报道.....有报道称......
5.It is estimated that 据估计.....
6..It is believed that 据信......大家相信......2013-06-15