Hello, fellas. Today we are going to learn about expressions of quantity in relative clauses. An expression of quantity is used to express the number or amount of something. It may precede a noun whose number or amount it describes. Several examples of expressions of quantity are one, two, each, every, both, some, several, a few, a little, many, much, most, etc.
(More on expressions of quantity: https://englishtips4u.com/2017/03/05/engclass-expressions-of-quantity/)
In relative clauses, expressions of quantity with of come before the pronouns. However, the pronouns are only whom, which and whose. This pattern is preceded by a comma and more common in writing than speaking.
1) There are 23 players in the German national team. Most of them are from Bayern Munich. (There are 23 players in the German national team, most of whom are from Bayern Munich.)
2) Pramoedya Ananta Toer wrote several books. Two of them are “Bumi Manusia” and “Anak Semua Bangsa”. (Pramoedya Ananta Toer wrote several books, two of which are “Bumi Manusia” and “Anak Semua Bangsa”.)
3) Students are reading the biography of Wolfgang Amadeus Mozart. One of his works is “The Marriage of Figaro”. (Students are reading the biography of Wolfgang Amadeus Mozart, one of whose works is “The Marriage of Figaro”.)
Betty Schrampfer Azar, Understanding and Using English Grammar: Third Edition