Inversion (đảo ngữ nhấn mạnh)

1. Nguyên tắc Khi đưa **trạng từ phủ định hoặc hạn chế** lên đầu câu, mệnh đề chính phải **đảo trợ động từ ra trước chủ ngữ** — giống cấu trúc câu hỏi.

• I have never seen such beauty. → Never have I seen such beauty.
• She rarely goes out. → Rarely does she go out.

2. Các trạng từ gây đảo ngữ - **Never, Rarely, Seldom, Hardly ever, Scarcely, Barely, Little, In no way, Nowhere, At no time, By no means, Under no circumstances, On no account.**

Ví dụ: - Under no circumstances should you open this door. - At no time did I feel unsafe.

3. Cặp cấu trúc đặc trưng ### Hardly / Scarcely / Barely ... when - *Hardly had I sat down **when** the phone rang.* - *Scarcely had we arrived **when** it started raining.*

No sooner ... than - *No sooner had I sat down **than** the phone rang.* - Chú ý: **when** đi với hardly/scarcely; **than** đi với no sooner.

Not only ... but also - *Not only does she sing, **but** she also dances.* - *Not only did he apologize, but he also paid for the damage.*

Only + trạng từ - *Only when he called did I understand.* - *Only after finishing my homework did I go out.* - *Only in this way can we solve the problem.*

4. Câu điều kiện đảo ngữ (không cần "if") - Type 1: *Should you need help, call me.* (= If you should need help) - Type 2: *Were I you, I would leave.* (= If I were you) - Type 3: *Had I known, I would have told you.* (= If I had known)

5. Trợ động từ chọn thế nào? | Câu gốc | Trợ động từ khi đảo | |---------|---------------------| | Present Simple | do / does | | Past Simple | did | | Present Perfect | have / has | | Past Perfect | had | | Modal | modal + S + V | | be | be + S |

6. Bẫy thường gặp - Quên **when** sau hardly/scarcely: ✗ *Hardly had I arrived and...* → ✓ *Hardly had I arrived when...* - Quên **than** sau no sooner: ✗ *No sooner had I sat down when...* → ✓ *No sooner had I sat down than...* - Dùng V thường thay vì V bare sau modal: ✗ *Should you needed* → ✓ *Should you need*.