Trạng từ quan hệ

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?