Các trạng từ quan hệ where, when & why có thể được sử dụng để nối các câu hoặc mệnh đề. Chúng thay thế cấu trúc trang trọng hơn của preposition + which dùng để giới thiệu một mệnh đề quan hệ.
| Cấu trúc trang trọng, giới từ + which | Cấu trúc phổ biến hơn dùng trạng từ quan hệ |
|---|---|
| That's the restaurant in which we met for the first time. | That's the restaurant where we met for the first time. |
| That picture was taken in the park at which I used to play. | That picture was taken in the park where I used to play. |
| I remember the day on which we first met. | I remember the day when we first met. |
| There was a very hot summer the year in which he was born. | There was a very hot summer the year when he was born. |
| Tell me the reason for which you came home late. | Tell me (the reason) why you came home late. |
| Do you want to know the reason for which he is angry with Sally? | Do you want to know (the reason) why he is angry with Sally? |