1. On the way home, we saw a lot of men, women and dogs which were playing in the park.
=> that (phần cụm danh từ gồm cả người lẫn vật => ko dùng which)
2. The man whom remained in the office was the manager.
=> who (whom dùng thay thế cho danh từ làm tân ngữ, mà câu này danh từ làm chủ ngữ)
3. This novel, which written by a well-known writer, should be read.
=> which is written (dạng bị động)
4. My friend George, that arrived late, was not permitted to enter the class.
=> who (sau dấu "," không dùng "that")
5. This is the only place which I can obtain scientific information.
=> where (= giới từ + which)
6. Chemistry is one branch of science on that most of the industries depend.
=> which (sau giới từ không dùng "that")
7. 1975 is the year in when the revolution took place.
=> bỏ "in" (đã dùng "when" (= in which) thì không dùng giới từ)
8. Mr. Brown, that teaches me English, is coming today.
=> who (sau dấu "," không dùng "that")
9. The hotel where we stayed in last year was excellent.
=> bỏ "in" (đã dùng trạng từ quan hệ "where" => không điền giới từ nữa)
10. At last they found the woman and her cat which were badly injured by the fire.
=> that (phần cụm danh từ gồm cả người lẫn vật => ko dùng which)