- To make mistakes is human.
- It's easy to play the piano, but it's very difficult to play well. （仮S真S）
- It was difficult for us to hear what she was saying. （仮S真S：to不定詞の意味上の主語を前置詞forを使って表す）
- It's kind of you to help. （仮S真S：性格、性質を表す場合には前置詞of）
［補語］
- To know all is to forgive all.
- My dream is to became teacher.
- The purpose of his absence was to search his dog.
［他動詞の目的語］
- I like to play basketball. （SVO）
- They decided to start a business together. （SVO）
- I want you to go there. （SVOO）
- His call reminds me to do my homework. （SVOO）
- He find it difficult to speak English fluently. （仮O真O）
- I thought it strange for her to have married with such an old man. （仮O真O）
［疑問詞付きto不定詞］
必ず名詞用法で使われる。
→ 疑問代名詞：what, which, who
→ 疑問限定詞：what, which, whose
→ 疑問副詞：when, where, why, how （※why to do は使われない）
→ 接続詞：whether （※疑問詞ではないが同じ用法のためここで扱う）
- I don't know what to do today.（疑問代名詞：what）
- She was perplexed which to buy. （疑問代名詞：which）
- I asked coach who to interview with the reporter. （疑問代名詞：who）
- We discussed in what color to make a new product. （疑問限定詞：what）
- I need to decide which club to participate in. （疑問限定詞：which）
- We're not sure whose plan to chose. （疑問限定詞：whose）
- When to start isn't important to me. （疑問副詞：when）
- She is wondering where to study abroad. （疑問副詞：where）
- Please show me how to use this tool. （疑問副詞：how）
- I didn’t know whether to take this bus or not. （接続詞：whether）
※日記 に補足があります。
→ 文法 #71 to不定詞（形容詞用法）
→ 文法 #72 to不定詞（副詞用法）
