Unit 77: Prefixes

Can-do: I can identify and use common prefixes to understand and form new words.
Level: A2
[IMAGE GENERATION PROMPT: A colorful graphic illustration showing a prefix ‘un-‘ merging with a base word ‘happy’ to form a single giant word puzzle pieces connecting together, high contrast, clean classroom setting style]

1. Target Vocabulary (Từ vựng mục tiêu)

Word & POS Definition & Translation Contextual Example
unhappyadj not happy or sad
không hạnh phúc, buồn rầu		 She was unhappy because she lost her favorite toy.
rewriteverb to write something again
viết lại		 The teacher asked me to rewrite the paragraph.
disagreeverb to have a different opinion
không đồng ý		 I disagree with you about the best movie.
preheatverb to heat an oven before using it
làm nóng trước		 You should preheat the oven to 200 degrees.
unluckyadj not having good luck
không may mắn		 He was unlucky and missed the bus by one minute.
reappearverb to appear or be seen again
xuất hiện lại		 The moon will reappear from behind the clouds.
disappearverb to go away so that it cannot be seen
biến mất		 The rabbit seemed to disappear into the hat.
unusualadj not common or ordinary
bất thường, lạ kì		 It is unusual to have such hot weather in October.

2. Grammar Theory (Ngữ pháp cơ bản)

Grammar Point 1: Introduction to Prefixes (Giới thiệu về Tiền tố)

A prefix is a letter or group of letters added to the beginning of a base word to change its meaning and create a new word.

Prefix + Base Word = New Word

Examples (Ví dụ):

  • Adding ‘un-‘ to ‘kind’ creates the new word ‘unkind’ (tàn nhẫn, không tốt bụng).
  • Adding ‘re-‘ to ‘play’ creates the new word ‘replay’ (chơi lại, tái phát).
  • Adding ‘dis-‘ to ‘like’ creates the new word ‘dislike’ (không thích).
[IMAGE GENERATION PROMPT: A simple, minimal table diagram displaying ‘Prefix’, ‘Base Word’, and ‘New Meaning’ clearly labeled with arrows indicating modification, designed for school book graphics]

Grammar Point 2: Meanings of Common Prefixes (Ý nghĩa của các tiền tố thông dụng)

Prefixes have specific meanings: ‘un-‘ and ‘dis-‘ mean ‘not’ or ‘opposite of’, while ‘re-‘ means ‘again’.

[un / dis / re] + Base Word

Examples (Ví dụ):

  • The story was unbelievable, which means it was not believable (không thể tin được).
  • I need to refill my glass, which means to fill it again (làm đầy lại).
  • They disobey the rules, which is the opposite of obeying (không tuân thủ, mos trái lệnh).

3. Practice Exercises (Bài tập thực hành)

Exercise 1: Vocabulary Matching

Match the vocabulary words on the left with their definitions or synonyms on the right.

1. unhappy
2. rewrite
3. disagree
4. preheat
5. unlucky
6. reappear
7. disappear
A. to write something again
B. not having good luck
C. to go away so that it cannot be seen
D. to have a different opinion
E. not happy or sad
F. to heat an oven before using it
G. to appear or be seen again
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. E – unhappy means not happy or sad.Unhappy có nghĩa là buồn hoặc không hạnh phúc.
2. A – rewrite means to write something again.Rewrite mang ý nghĩa viết lại một văn bản nào đó.
3. D – disagree means to have a different opinion.Disagree biểu thị sự bất đồng ý kiến, không đồng ý.
4. F – preheat means to heat an oven before using it.Preheat có nghĩa là làm nóng lò trước khi nấu nướng.
5. B – unlucky means not having good luck.Unlucky tức là xui xẻo, không gặp may mắn.
6. G – reappear means to appear or be seen again.Reappear có nghĩa là xuất hiện trở lại.
7. C – disappear means to go away so that it cannot be seen.Disappear có nghĩa là biến mất khỏi tầm mắt.
Exercise 2: Gap Fill

Fill in the blanks with the correct prefix words from the box below.

unhappy | rewrite | disagree | preheat | unlucky | reappear | disappear | unusual
  • 1. Please the oven to 180 degrees before baking the cake.
  • 2. He was very because he failed his driving test.
  • 3. I watched the magician make the coin from his hand.
  • 4. My draft had too many mistakes, so I had to it.
  • 5. It is very to see snow in this warm region.
  • 6. Tim was so ; it started raining right when he stepped outside.
  • 7. After a long winter, the green leaves finally on the branches.
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. preheat – You need to heat the oven before baking.Cần làm nóng lò trước khi nướng bánh.
2. unhappy – Failing a test makes a person feel sad/not happy.Trượt bài kiểm tra làm ai đó buồn bã/không vui.
3. disappear – Magicians make things go away so they cannot be seen.Ảo thuật gia làm đồng xu biến mất khỏi tay.
4. rewrite – Making too many mistakes requires writing the text again.Quá nhiều lỗi sai yêu cầu phải viết lại từ đầu.
5. unusual – Snow in a warm region is rare and not ordinary.Tuyết rơi ở vùng ấm áp là hiện tượng kỳ lạ, bất thường.
6. unlucky – Getting caught in sudden rain implies bad luck.Vừa bước ra ngoài trời đổ mưa chứng tỏ không may mắn.
7. reappear – Leaves showing up again after winter.Lá cây xuất hiện trở lại trên cành sau mùa đông dài.
Exercise 3: Multiple Choice Question

Choose the correct option that best completes the sentence or defines the prefix.

  • 1. What does the prefix ‘re-‘ mean in words like ‘rewrite’ or ‘reappear’?
    A. Not
    B. Again
    C. Opposite of
    D. Before
  • 2. If you disagree with someone, it means you:
    A. Share the opinion
    B. Do not have the same opinion
    C. Like them
    D. Listen again
  • 3. Choose the adjective that means “not common or ordinary”:
    A. unusual
    B. rewrite
    C. preheat
    D. disappear
  • 4. Which prefix means ‘before’ or ‘in advance’?
    A. un-
    B. re-
    C. pre-
    D. dis-
  • 5. What is the base word of ‘unlucky’?
    A. un
    B. luck
    C. lucky
    D. luckily
  • 6. The sun will _______ from behind the dense storm clouds soon.
    A. reappear
    B. preheat
    C. rewrite
    D. disagree
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. B – The prefix ‘re-‘ signifies repetition or ‘again’.Tiền tố ‘re-‘ biểu thị hành động lặp lại (một lần nữa).
2. B – Disagree implies having a different/opposite view.Disagree có nghĩa là không cùng chung ý kiến, bất đồng.
3. A – ‘Unusual’ matches the definition of being uncommon.‘Unusual’ có nghĩa là không bình thường, hiếm gặp.
4. C – ‘Pre-‘ means doing something before or in advance.‘Pre-‘ chỉ hành động diễn ra trước hoặc làm trước.
5. C – The primary adjective base is ‘lucky’, to which ‘un-‘ is added.Từ gốc ở đây là tính từ ‘lucky’, thêm tiền tố ‘un-‘.
6. A – The sun will show up again, meaning it will ‘reappear’.Mặt trời sẽ xuất hiện trở lại sau những đám mây.
[IMAGE GENERATION PROMPT: An illustrative cartoon picture of a student looking at a blackboard containing prefix examples, scratching head, thinking icon above, colorful educational style]
Exercise 4: True / False

Read the statements below and determine if they are True (T) or False (F) based on prefix rules.

  • 1. The prefixes ‘un-‘ and ‘dis-‘ can both mean ‘not’ or ‘opposite of’. ( T / F )
  • 2. ‘Preheat’ means heating the kitchen oven after you finish cooking the food. ( T / F )
  • 3. The word ‘rewrite’ means to erase everything and never write it again. ( T / F )
  • 4. When an object disappears, it means you can easily see it. ( T / F )
  • 5. ‘Unusual’ is an adjective used for common, everyday occurrences. ( T / F )
  • 6. Adding a prefix changes the core meaning of the base word. ( T / F )
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. True – Both prefixes mean negation or opposition.Đúng, cả hai tiền tố đều chỉ sự phủ định hoặc trái ngược.
2. False – Preheat means heating beforehand, not after cooking.Sai, preheat là làm nóng trước chứ không phải sau khi nấu.
3. False – Rewrite means writing something over again.Sai, rewrite nghĩa là viết lại chứ không phải xóa đi bỏ luôn.
4. False – Disappear means it goes away and cannot be seen.Sai, biến mất nghĩa là không thể nhìn thấy được nữa.
5. False – Unusual means NOT common, unique, or strange.Sai, unusual nghĩa là bất thường, không phải phổ biến.
6. True – Yes, prefixes alter meanings and form new words.Đúng, tiền tố làm thay đổi ngữ nghĩa ban đầu của từ gốc.
Exercise 5: Sentence Reordering

Rearrange the words given below to make meaningful sentences containing prefix words.

  • 1. because / toy / lost / she / unhappy / was / her / .
    ➔ ___________________________________________________________
  • 2. paragraph / teacher / asked / to / rewrite / the / me / .
    ➔ ___________________________________________________________
  • 3. with / best / movie / I / about / the / disagree / you / .
    ➔ ___________________________________________________________
  • 4. should / degrees / oven / preheat / you / 200 / to / the / .
    ➔ ___________________________________________________________
  • 5. missed / bus / unlucky / he / and / was / the / .
    ➔ ___________________________________________________________
  • 6. behind / will / the / moon / reappear / clouds / from / .
    ➔ ___________________________________________________________
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. She was unhappy because she lost her toy.Cô ấy đã không vui/buồn vì làm mất đồ chơi.
2. The teacher asked me to rewrite the paragraph.Giáo viên yêu cầu tôi viết lại đoạn văn này.
3. I disagree with you about the best movie.Tôi không đồng ý với bạn về bộ phim hay nhất.
4. You should preheat the oven to 200 degrees.Bạn nên làm nóng lò trước ở mức 200 độ.
5. He was unlucky and missed the bus.Anh ấy đã không may mắn và lỡ chuyến xe buýt.
6. The moon will reappear from behind the clouds.Mặt trăng sẽ xuất hiện lại từ sau những đám mây.
Exercise 6: Grammar Selection

Select the proper base word or prefix combination to fit the contextual meaning provided in brackets.

  • 1. If you want to watch the clip again, press [ unplay / replay / display ]. (Meaning: play it again)
  • 2. Her behavior was quite [ unusual / reusual / disusual ] for a quiet child. (Meaning: not common)
  • 3. He managed to [ unappear / reappear / disappear ] into the thick fog. (Meaning: go away out of sight)
  • 4. I had to [ reheat / unheat / disheat ] the soup because it got cold. (Meaning: heat it again)
  • 5. Don’t worry, it is [ unpossible / impossible / redispossible ] to lose your way with a map. (Meaning: not possible)
  • 6. They completely [ redisagree / disagree / undisagree ] on the proposal. (Meaning: opposite of agreeing)
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. replay – ‘re-‘ means again, so replay is to play again.Replay có nghĩa là phát lại hoặc chơi lại một đoạn phim/nhạc.
2. unusual – ‘un-‘ paired with usual means rare/not common.Unusual nghĩa là kỳ lạ, không bình thường.
3. disappear – ‘dis-‘ combined with appear means to vanish.Disappear có nghĩa là biến mất hoàn toàn vào màn sương.
4. reheat – To heat something up again calls for the ‘re-‘ prefix.Reheat có nghĩa là làm nóng lại món súp đã nguội.
5. impossible – While ‘un-‘ means not, ‘possible’ specifically takes ‘im-‘ (a variant of in-) to mean not possible.Impossible nghĩa là không thể (tuy ‘un-‘ cũng có nghĩa là không nhưng ‘possible’ đi với ‘im-‘).
6. disagree – ‘dis-‘ is the correct negative prefix for the verb agree.Disagree là tiền tố phủ định chuẩn xác đi kèm động từ agree.
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