【几点注意】
1.“be said+不定式”结构只有被动式，没有主动式。如：
据说他懂得许多语言。
正：He is said to know many languages.
误：They say him to know many languages.
但是，可以换成it’s said that…句式。如：
正：It is said that he knows many languages. (from www.hxen.com)
2.“be said+不定式”结构中的不定式有时可能是目的状语。如：
These words were said to frighten you. 说那些话是为了吓唬你。
【思维发散】与“be said+不定式”结构相似的还有“be reported (believed, supposed, thought, etc) + 不定式”等，其用法和搭配均大致相同。如：
She is believed to be staying with her aunt. 可以相信她住在她姑姑家里。
There is supposed to be a train at 12:37. 12点37分想必有一班火车。(from www.hxen.com)
Thousands were reported to be working as slaves there. 据报导数以千计的人在那里作奴隶。
He is reported to have been chosen chairman of the trade union. 据说他当选了工会主席。