b
1 be said to have done sth :发生在谓语动词之前,to是动词原形的标志,所以to后面用动词原形
2 be said to +动词原形
3 相同的结构还有
be thought to
be believed to + do / be done
be reported to + be doing
be considered to + have( been) done
be known to
be found to不是说句子里有两个谓语动词时先发生的用had done吗?你好。因为有了谓语动词,比如说,be found to ,后面就要用完成式的原形:I find that he was here last week.--------- == He is found to have been here last week.(仔细研读,你就明白了。祝你愉快。)