1. Sydney is the largest Australian city. It is not the capital od Australian (reducing the relative clauses) => 2. John works with that orther chap. I can't remember his name (whose) => 3. The man who jogs regulaly in the Botanic Gardens is swimming in his private pool. (reducing the relative clauses) =>

=>

1. Sydney, the largest Australian city, is not the capital of Australian. (rút gọn mđqh -> bỏ which is)

2. John works with that other chap whose name I can't remember.

-> whose: đtqh thay thế tính từ sở hữu

3. The man jogging regularly in the Botanic Gardens is swimming in his private pool.

-> rút gọn mđqh dạng chủ động (động từ chính ở dạng Ving)