HỌC NHANH NGỮ PHÁP TIẾNG ANH / Ngữ Pháp Trình Độ C1

1. Concept (Khái niệm)

Tense Shifts in Reported Speech (Chuyển đổi thì trong câu tường thuật) là quy tắc thay đổi thì động từ khi ta chuyển từ lời nói trực tiếp (Direct Speech) sang lời nói gián tiếp (Reported/Indirect Speech). Mục đích là để đảm bảo sự phù hợp về thời gian (time reference) giữa lời nói và thời điểm tường thuật.

• Direct Speech: “I am tired,” she said.
• Reported Speech: She said (that) she was tired.

---

2. Structure (Cấu trúc cơ bản)

A. Direct Speech → Reported Speech

Direct Speech	Reported Speech (Lùi thì)	Ví dụ (Example)
Present Simple	Past Simple	He said, “I study English.” → He said (that) he studied English.
Present Continuous	Past Continuous	She said, “I am reading.” → She said (that) she was reading.
Present Perfect	Past Perfect	He said, “I have finished.” → He said (that) he had finished.
Present Perfect Continuous	Past Perfect Continuous	She said, “I have been waiting.” → She said (that) she had been waiting.
Past Simple	Past Perfect	He said, “I saw her.” → He said (that) he had seen her.
Past Continuous	Past Perfect Continuous	She said, “I was cooking.” → She said (that) she had been cooking.
Future Simple (will)	would	He said, “I will call you.” → He said (that) he would call me.
Future Continuous	would be + V-ing	She said, “I will be studying.” → She said (that) she would be studying.
Future Perfect	would have + V3	He said, “I will have finished.” → He said (that) he would have finished.

Rule: Khi động từ tường thuật ở thì quá khứ (said, told, explained...), thì mệnh đề tường thuật phải lùi thì một bậc.

---

3. Usage (Cách dùng)

• Sử dụng trong lời nói gián tiếp (reported statements), câu hỏi gián tiếp và mệnh lệnh gián tiếp.
• Lùi thì chỉ cần thiết khi động từ tường thuật ở thì quá khứ.
• Nếu lời nói vẫn còn đúng hoặc là sự thật hiển nhiên, thì không cần lùi thì.

Ví dụ:

• He said (that) the Earth is round. ✅ (Không lùi thì – sự thật hiển nhiên)
• She said (that) she was tired. ✅ (Lùi thì – hành động đã qua)
• He told me he would come later. ✅ (Lùi thì – “will” → “would”)

---

4. Time & Place Shifts (Thay đổi từ chỉ thời gian và nơi chốn)

Direct Speech	Reported Speech
today	that day
yesterday	the day before / the previous day
tomorrow	the next day / the following day
now	then
ago	before
this	that
these	those
here	there
next week	the following week
last year	the previous year

Example:
Direct: “I’ll go there tomorrow.” → Reported: He said he would go there the next day.

---

5. Special Cases (Các trường hợp đặc biệt)

• Không lùi thì khi động từ chính ở hiện tại (say, tell, claim...) → He says (that) he loves music.
• Không lùi thì khi câu chứa sự thật, định luật, chân lý. → The teacher said (that) water boils at 100°C.
• Không lùi thì khi hành động vẫn đúng tại thời điểm nói. → She said she lives in London. (Cô ấy vẫn sống ở đó.)
• Động từ tình thái (modals):
  • will → would
  • can → could
  • may → might
  • must → had to
  • shall → should / would

---

6. Common Mistakes (Các lỗi thường gặp)

Lỗi sai	Sửa đúng	Giải thích
He said he is tired.	He said he was tired.	Động từ tường thuật ở quá khứ → cần lùi thì.
She told me she will come.	She told me she would come.	“will” → “would” khi lùi thì.
He said he has finished.	He said he had finished.	Present Perfect → Past Perfect.
They said they are working.	They said they were working.	Present Continuous → Past Continuous.
She said the Earth was round.	She said the Earth is round.	Sự thật hiển nhiên → không cần lùi thì.

---

7. Quick Memory Tips (Mẹo ghi nhớ nhanh)

• 👉 Khi động từ tường thuật ở quá khứ, hãy lùi thì 1 bậc (backshift one tense).
• 📌 Hiện tại → Quá khứ / Quá khứ → Quá khứ hoàn thành / Will → Would.
• ❌ Không lùi thì với sự thật hoặc trạng thái vẫn đúng hiện tại.
• 📖 Ghi nhớ nhanh:
  • am/is → was
  • are → were
  • have/has → had
  • will → would
  • can → could
  • may → might
• 🧠 Mẹo: Nếu trong câu có “said that” → kiểm tra xem cần lùi thì hay không.

---

8. Advanced Examples (Ví dụ nâng cao)

1. “I am working on a new project,” he said. → He said (that) he was working on a new project. → Anh ấy nói rằng anh ấy đang làm việc trong một dự án mới.
2. “We have completed the task,” they said. → They said they had completed the task. → Họ nói rằng họ đã hoàn thành nhiệm vụ.
3. “I will help you tomorrow,” she said. → She said she would help me the next day. → Cô ấy nói rằng cô ấy sẽ giúp tôi vào ngày hôm sau.
4. “I can play the guitar,” he said. → He said he could play the guitar. → Anh ấy nói rằng anh ấy có thể chơi guitar.
5. “The sun rises in the east,” the teacher said. → The teacher said the sun rises in the east. → Cô giáo nói rằng mặt trời mọc ở hướng đông (sự thật – không lùi thì).
6. “I was reading when he arrived,” she said. → She said she had been reading when he arrived. → Cô ấy nói rằng cô ấy đã đang đọc sách khi anh ta đến.
7. “I may come later,” he said. → He said he might come later. → Anh ấy nói rằng có thể anh ấy sẽ đến sau.
8. “I must leave now,” she said. → She said she had to leave then. → Cô ấy nói rằng cô ấy phải đi lúc đó.
9. “We are meeting tomorrow,” they said. → They said they were meeting the next day. → Họ nói rằng họ sẽ gặp nhau vào ngày hôm sau.
10. “I had finished before you called,” he said. → He said he had finished before I called. → Anh ấy nói rằng anh ấy đã hoàn thành trước khi tôi gọi.

---

9. Summary (Tổng kết ghi nhớ)

Thì trực tiếp	Thì gián tiếp	Ví dụ
Present Simple	Past Simple	He said he studied.
Present Continuous	Past Continuous	She said she was reading.
Present Perfect	Past Perfect	He said he had finished.
Past Simple	Past Perfect	She said she had seen it.
Will	Would	He said he would go.
Can	Could	She said she could help.
May	Might	He said he might come.
Must	Had to	She said she had to leave.

Tóm lại:
✅ Lùi thì 1 bậc khi tường thuật trong quá khứ.
✅ Giữ nguyên thì nếu sự thật vẫn đúng hoặc mang tính phổ quát.
✅ Chú ý chuyển đổi từ chỉ thời gian và nơi chốn.
➡️ “Will → Would, Is → Was, Have → Had” là ba quy tắc cơ bản nhất để nhớ nhanh.