1. My sister, _______________________________________________________________________________________________________________________________________________________ lives in America, is a nurse.
Đáp án: who
Giải thích: "Who" được dùng để thay thế cho danh từ chỉ người ("my sister").
2. He bought us a beautiful present, _______________________________________________________________________________________________________________________________________________________ was very kind of him.
Đáp án: which
Giải thích: "Which" được dùng để thay thế cho danh từ chỉ vật ("a beautiful present").
3. We bought this flat from a very nice family, _______________________________________________________________________________________________________________________________________________________ lived here for ten years.
Đáp án: who
Giải thích: "Who" được dùng để thay thế cho danh từ chỉ người ("a very nice family").
4. The people, _______________________________________________________________________________________________________________________________________________________ idea this was, should be ashamed!
Đáp án: whose
Giải thích: "Whose" được dùng để chỉ sự sở hữu ("idea" thuộc về "the people").
5. These houses are very popular, _______________________________________________________________________________________________________________________________________________________ shows that some people just don't understand architecture.
Đáp án: which
Giải thích: "Which" được dùng để thay thế cho cả mệnh đề phía trước ("These houses are very popular").
6. When I grow up, I want to live in Brighton, _______________________________________________________________________________________________________________________________________________________ is sometimes called the most exciting city in Britain outside of London.
Đáp án: 1 which  

1. My sister, who lives in America, is a nurse.

2. He bought us a beautiful present, which was very kind of him.

3. We bought this flat from a very nice family, who lived here for ten years.

4. The people, whose idea this was, should be ashamed!

5. These houses are very popular, which shows that some people just don’t understand architecture.

6. When I grow up, I want to live in Brighton, which is sometimes called the most exciting city in Britain outside of London.