using relative clause 1,the girls are performing the play.They rehearsed it yesterday 2,their parents are anxious about their children.The children come back late 3,the lecturer is my uncle . He gave an interesting talk on TV last night

1. The girls are performing the play. They rehearsed it yesterday.

=> The girls are performing the play which they rehearsed yesterday.

2. Their parents are anxious about their children. The children come back late.

=> Their parents are anxious about their children who come back late.

3. The lecturer is my uncle. He gave an interesting talk on TV last night.

=> The lecturer who gave an interesting talk on TV last night is my uncle.

Giải thích:

Cách sử dụng, chức năng của các đại từ quan hệ dùng trong 3 câu trên:

- Who : làm chủ ngữ, thay thế cho danh từ chỉ người 

- Which : làm chủ ngữ hoặc tân ngữ, thay thế cho danh từ chỉ đồ vật hoặc con vật.