［？］I saw a bird which was sitting on her hand.

・従来、関係代名詞の"that"は制限用法に、"which"は制限用法と非制限用法に使われている。
・しかし、シカゴマニュアルなどの主要な編集用参考文献に、「"that"は制限用法に、"which"は非制限用法に使う」と書かれているため、プロのライターはその規定に従うざるを得ないというのが現状である。
・当然のことながら、文法学者からの批判はある。

《従来の用法》
［正］I saw a bird which was sitting on her hand.
［正］I saw a bird, which was sitting on her hand.
［正］I saw a bird that was sitting on her hand.
［誤］I saw a bird, that was sitting on her hand.

《編集用参考文献》
［誤］I saw a bird which was sitting on her hand.
［正］I saw a bird, which was sitting on her hand.
［正］I saw a bird that was sitting on her hand.
［誤］I saw a bird, that was sitting on her hand.

［？］I saw a bird which was sitting on her hand.の関連項目

• ⇒ 関係代名詞の主格
• ⇒ 関係代名詞の所有格
• ⇒ 関係代名詞の目的格
• ⇒ 関係代名詞が前置詞の目的語になる場合
• ⇒ 関係代名詞"that"と"which"
• ⇒ I have a dog who plays Frisbee well.