Câu chẻ được dùng để nhấn mạnh một thành phần của câu như chủ ngữ, túc từ hay trạng từ
1. Nhấn mạnh chủ từ (Subject focus)
Ex: My brother collected these foreign stamps.
→ It was my brother who collected these foreign stamps.
Ex: Her absence at the party made me sad.
→ It was her absence at the party that made me sad.
2. Nhấn mạnh túc từ (Object focus)
Ex: I met Daisy on the way to school.
→ It was Daisy who(m) I met on the way to school.
Note: Khi nhấn mạnh túc từ ta có thể dùng who thay cho whom nhưng khi nhấn mạnh chủ từ thì không dùng whom thay cho who.
Ex: My brother bought an old motorbike from our neighbor.
→ It was an old motorbike that my brother bought from our neighbor.
3. Nhấn mạnh trạng từ (Adverbial focus)
Ex: - We first met in December.
→ It was in December that we first met.
- Phan Thanh Gian was born in this village.
→ It was in this village that Phan Thanh Gian was born.