関係代名詞 which の難しい用法。ただし、制限用法（限定用法）と非制限用法（非限定用法）による意味の違い（カンマのあるなし）、冠詞の a と the による意味の違いについては、さらに難しくなるので、とりあえず例を列挙するが、意味の解釈は割愛。
which の前に前置詞が付く場合。
１．This is the box in which I keep my treasure.
２．This is a box in which I keep my treasure.
３．This is the box, in which I keep my treasure.
４．This is a box, in which I keep my treasure.
which の前に名詞＋前置詞が付く場合。
５．I liked my grandfather's house the roof of which was yellow.
６．I liked my grandfather's house, the roof of which was yellow.
これらは whose を使って書くことも可能。
I liked my grandfather's house whose roof was yellow.
I liked my grandfather's house, whose roof was yellow.
主節の先行詞と同格の語句（言い替えた語句）を、先行詞としてもう一度、繰り返して提示。
７．I like apples, oranges, and pineapples, the fruits which are essential for me.
同格に近い。先行詞を繰り返して提示、明示する方法。先行詞と関係代名詞が離れている場合など。
８．The problems for foreigners of conducting reserach at the major Japanese universities, problems which are well known to most vitisiting scholars, are numerous and deep-rooted.
＊マーク・ピーターセン『日本人の英語』（岩波新書）より。
より高度な使い方。先行詞を手直しして which 節中で使う。これも先行詞と関係代名詞が離れている場合。上記７．および８．との、語句の順番の違いに注意！
９．The lyrics of that song were written on a word processor, the appeal of which lyrics would seem to lie mainly in their clever rhyming and puns.
＊マーク・ピーターセン『日本人の英語』（岩波新書）より。
10．The lyrics of that song were written on a word processor, which lyric's appeal would seem to lie mainly in their clever rhyming and puns.（lyric's は lyrics' の間違い？）
＊マーク・ピーターセン『日本人の英語』（岩波新書）より。