完了不定詞のポイントをまとめています。時制のズレを表すときに、to have 過去分詞形という語順で、完了不定詞を使います。
不定詞の完了形(完了不定詞) は、動名詞と同様、不定詞で表される行為がいつのことであるかをはっきりさせるために、不定詞の単純形と完了形とが使い分けられる。単純形は(to+動詞の原形)であり、完了形は（to have+過去分詞)の形になる。そのあたりについて、詳しく記述しています。それでは、高校英文法「不定詞の完了形（完了不定詞）」まとめです。
（単純形）Ann is said to be their leader.(アンは、現在の彼らの指導者であると(現在)言われている)
（完了形）Ann is said to have been their leader.(アンは、(以前)彼らの指導者であったと(現在)言われている)
（単純形）to be は時制の基準となる述語動詞isと同じ「時」のことを表し、（完了形）to have beenは、述語動詞isより以前の「時」を表している。
- Ann is said to be their leader.=It is said that Ann is their leader.
- Ann is said to have been their leader. =It is said that Ann was (has been) their leader.
1.Ann was said to be their leader. (アンは「その時彼らの指導者であると「その時)言われていた)
= It was said that Ann was their leader.
2.Ann was said to have been their leader. (アンは「その時」以前)彼らの指導者だったと(その時言われていた)
= It was said that Ann had been their leader.
3.He seems to be ill. (彼は病気であるようだ)
= It seems that he is ill.
4.He seems to have been ill yesterday. (彼は昨日病気だったようだ
= It seems that he was ill yesterday.
5.He seems to have been ill since last weekend. (彼は先週末以来ずっと病気であるようだ)
= It seems that he has been ill since last weekend.
6.He seemed to be ill. (彼は病気であるようだった)
= It seemed that he was ill.
7.He seemed to have been ill. (彼は病気だったようだった)
= It seemed that he had been ill.
8.They were thought to have died many years before. (彼らは何年も前に死んだと思われていた)
= It was thought that they had died many years before.
9.I am sorry to have missed the TV program last night. (私は昨夜そのテレビ番組を見逃してしまって残念だ)
= I am sorry that I missed the TV program last night.