Unit 53: Complex Sentences
Can-do Goal: I can identify and form complex sentences using independent and dependent clauses.
1. Vocabulary Focus
Review the essential words below. These terms will be used throughout the sentence structures and practice tasks.
| Word & POS | Definition & Example | Vietnamese Translation |
|---|---|---|
| hamster (noun) |
a small furry animal with a short tail, often kept as a pet. “My sister’s hamster was very sick and needed help.” |
chuột hamster |
| veterinarian (noun) |
a doctor who treats sick or injured animals. “I took the small animal to the veterinarian for a check-up.” |
bác sĩ thú y |
| examine (verb) |
to look at someone or something very carefully. “After examining the pet, the doctor knew what was wrong.” |
khám, kiểm tra |
| medicine (noun) |
a substance used to treat an illness or injury. “The doctor gave her some medicine to feel better.” |
thuốc |
| administer (verb) |
to give a treatment or a dose of medicine to someone. “Andrea could not administer the medicine to her pet properly.” |
cho uống thuốc, cung cấp |
| properly (adverb) |
in a way that is correct or suitable. “You must follow the instructions to use the tool properly.” |
một cách đúng đắn |
| exercise wheel (noun) |
a circular device for small animals to run in for exercise. “The healthy hamster was running on her exercise wheel again.” |
bánh xe chạy tập thể dục |
| perk up (verb) |
to become more lively, active, or cheerful. “When the pet began to perk up, my sister felt much happier.” |
trở nên tươi tỉnh, khỏe lại |
2. Grammar Theory
Grammar Point 1: Complex Sentences
A complex sentence combines one independent clause (which expresses a complete thought and can stand alone) with one or more dependent clauses (which do not express a complete thought and cannot stand alone).
Structure:
Independent Clause + Dependent Clause(No comma needed)Dependent Clause + , + Independent Clause(Comma required after the dependent clause)
Examples:
- “When I saw how sad Andrea was, I wanted to help.”
- “I took Minnie to the veterinarian even though I don’t like hamsters.”
- “Before we knew it, she was running on her exercise wheel.”
Grammar Point 2: Subordinating Conjunctions
A dependent clause always starts with a subordinating conjunction (such as when, because, after, although, before, even though, if). It connects the dependent clause to the main clause and establishes a relationship of time, cause, or contrast.
Structure: Subordinating Conjunction + Subject + Verb
Examples:
- “I gave Minnie the medicine because Andrea couldn’t do it.” (Cause/Reason)
- “After Dr. Rains examined the hamster, he gave us a prescription.” (Time relationship)
- “When Minnie began to perk up, everyone felt relieved.” (Time relationship)
3. Guided Practice
Exercise 1: Vocabulary Matching
Match the vocabulary words (1-7) with their corresponding meanings or definitions (A-G).
1. Hamster
2. Veterinarian
3. Examine
4. Medicine
5. Administer
6. Properly
7. Perk up
A. To look at someone or something very carefully.
B. To give a treatment or a dose of medicine to someone.
C. In a way that is correct, suitable, or accurate.
D. A small furry animal with a short tail, often kept as a pet.
E. A doctor who specializes in treating sick or injured animals.
F. To become more lively, active, healthy, or cheerful.
G. A substance used to treat an illness, disease, or medical injury.
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1 – D: Hamster is a small furry pet animal. (Chuột hamster là loài động vật nhỏ lông xù nuôi làm cảnh).
2 – E: Veterinarian is an animal doctor. (Bác sĩ thú y là bác sĩ chữa trị cho động vật).
3 – A: Examine means to look at very carefully. (Examine nghĩa là khám hoặc kiểm tra cẩn thận).
4 – G: Medicine is a substance used for treatment. (Medicine là dược phẩm, thuốc dùng để chữa bệnh).
5 – B: Administer means to give/apply medicine. (Administer nghĩa là cấp thuốc hoặc cho uống thuốc).
6 – C: Properly means doing something correctly. (Properly nghĩa là một cách đúng đắn, chính xác).
7 – F: Perk up means to become lively or healthy again. (Perk up nghĩa là tươi tỉnh hoặc khỏe khoắn trở lại).
Exercise 2: Fill in the Blanks (Vocabulary Focus)
Complete each sentence using one word or phrase from the box: [hamster, veterinarian, examine, medicine, administer, properly, exercise wheel, perk up].
- We took our small __________ to the animal clinic last night because it wouldn’t eat.
- The kind __________ gently picked up the little animal to look at its paws.
- The doctor needs to __________ the pet thoroughly before deciding on a treatment plan.
- Andrea had to buy special liquid __________ to treat her pet’s respiratory infection.
- It is sometimes very difficult to __________ pills to a tiny animal safely.
- If you don’t clean the cage __________, your pet might catch harmful bacteria and get sick.
- The active creature spent hours running fast inside its spinning __________.
- A few hours after drinking water, the weak pet started to __________ and look active again.
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. hamster Context points to a small pet animal. (Ngữ cảnh chỉ một con thú cưng nhỏ).
2. veterinarian The doctor at an ‘animal clinic’ is a vet. (Bác sĩ tại phòng khám động vật là bác sĩ thú y).
3. examine A doctor must inspect/look closely at a pet first. (Bác sĩ cần khám/kiểm tra kỹ trước).
4. medicine ‘Liquid medicine’ fits the treatment description. (Thuốc dạng lỏng phù hợp với việc chữa trị).
5. administer To ‘administer pills’ means giving medication. (Cho động vật nhỏ uống thuốc viên).
6. properly An adverb is needed to modify ‘clean’ (clean properly = dọn dẹp một cách đúng đắn, sạch sẽ).
7. exercise wheel ‘Running inside its spinning…’ indicates the toy. (Chạy bên trong thứ đang xoay chỉ bánh xe tập thể dục).
8. perk up Means to regain energy and look lively. (Trở nên tươi tỉnh và nhanh nhẹn trở lại).
Exercise 3: Multiple Choice (Grammar Structure)
Choose the best option (A, B, C, or D) to complete each complex sentence correctly.
- __________ the veterinarian examined the sick hamster, he immediately prescribed some medicine.
- The little pet began to perk up __________ Andrea gave it the accurate dose.
- __________ we followed all the instructions properly, the animal’s condition did not improve at first.
- You should clean the exercise wheel __________ it gets dirty or sticky.
- Andrea stayed awake late at night __________ she could monitor her sick hamster’s health.
- The hamster cannot run safely __________ you fix its broken exercise wheel properly.
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. B – After: Establishes a logical sequence of time. (Sau khi bác sĩ khám xong thì kê đơn thuốc).
2. C – because: Introduces the reason why the pet perked up. (Thú cưng tỉnh táo lại vì được cho uống đúng liều).
3. A – Although: Expresses contrast between following rules and lack of improvement. (Mặc dù làm đúng hướng dẫn nhưng lúc đầu chưa tiến triển).
4. A – whenever: Means at any time that it happens. (Nên lau bánh xe chạy bất cứ khi nào nó bị bẩn).
5. A – so that: Expresses purpose (In order that / so that + clause). (Thức muộn để mà có thể theo dõi sức khỏe của thú cưng).
6. C – unless: Means ‘if not’ (if you don’t fix it). (Chuột không thể chạy an toàn trừ khi bạn sửa bánh xe đúng cách).
Exercise 4: True or False (Clause Identification)
Read each statement about the underlined part of the complex sentence. Write T (True) or F (False).
- In the sentence: “When the hamster perked up, Andrea smiled,” the underlined part is an independent clause. (____)
- In the sentence: “We must go to the veterinarian because the pet is injured,” the underlined part is a dependent clause. (____)
- In the sentence: “Andrea administered the medicine properly although she was very nervous,” the underlined part can stand alone as a complete sentence. (____)
- In the sentence: “Before the doctor examined the animal, he washed his hands,” the underlined part requires a comma after it because it comes first. (____)
- In the sentence: “The hamster ran on its wheel until the sun came up,” the underlined part contains a coordinating conjunction. (____)
- In the sentence: “Even though hamsters are small pets, they require a lot of careful attention,” the underlined part expresses a complete thought. (____)
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1. F: It starts with ‘When’, making it a dependent clause. (Sai, đây là mệnh đề phụ thuộc vì có từ ‘When’).
2. T: It starts with ‘because’ and cannot stand alone. (Đúng, mệnh đề trạng ngữ chỉ lý do là mệnh đề phụ thuộc).
3. T: It is an independent clause and expresses a complete, standalone thought. (Đúng, đây là mệnh đề độc lập có thể tách riêng).
4. T: When a dependent clause is placed at the beginning, a comma must follow it. (Đúng, mệnh đề phụ thuộc đứng đầu câu cần dấu phẩy).
5. F: ‘Until’ is a subordinating conjunction, not coordinating. (Sai, ‘Until’ là liên từ phụ thuộc chứ không phải liên từ kết hợp).
6. F: It is a dependent clause; it leaves the thought incomplete without the main clause. (Sai, mệnh đề phụ thuộc không diễn đạt ý trọn vẹn).
Exercise 5: Sentence Reordering (Punctuation & Syntax)
Rearrange the words to create grammatically correct complex sentences. Pay close attention to punctuation (commas).
- medicine / After / the / veterinarian / gave / us / the / . / perked / hamster / up / the
_________________________________________________________________________________ - could / Andrea / administer / because / was / sick / not / she / the / pills / .
_________________________________________________________________________________ - examined / When / doctor / the / pet / , / it / was / very / quiet / the / .
_________________________________________________________________________________ - wheel / exercise / ran / on / its / The / hamster / although / it / tired / was / .
_________________________________________________________________________________ - properly / follow / instructions / If / you / the / , / the / pet / will / heal / fast / .
_________________________________________________________________________________ - before / we / took / it / The / home / clinic / at / the / stayed / hamster / .
_________________________________________________________________________________
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1: After the veterinarian gave us the medicine, the hamster perked up. Requires a comma because the ‘After’ clause starts the sentence. (Cần dấu phẩy do mệnh đề trạng ngữ thời gian đứng đầu).
2: Andrea could not administer the pills because she was sick. No comma is needed when ‘because’ connects clauses in the middle. (Không dùng dấu phẩy khi mệnh đề ‘because’ đứng sau).
3: When the doctor examined the pet, it was very quiet. ‘When’ clause at the beginning requires a separating comma. (Mệnh đề ‘When’ ở đầu câu đòi hỏi dấu phẩy ngăn cách).
4: The hamster ran on its exercise wheel although it was tired. ‘Although’ introduces contrast; no comma needed in standard modern mid-position. (Mệnh đề chỉ sự nhượng bộ ở vế sau không cần dấu phẩy).
5: If you follow the instructions properly, the pet will heal fast. Conditional ‘If’ clause at the front requires a comma. (Mệnh đề điều kiện đứng trước đòi hỏi có dấu phẩy ở giữa).
6: The hamster stayed at the clinic before we took it home. Time clause with ‘before’ comes second, so no comma is applied. (Mệnh đề với ‘before’ đứng sau nên không dùng dấu phẩy).
Exercise 6: Grammar Selection & Combining
Combine the two simple sentences into one complex sentence using the subordinating conjunction provided in brackets. Add commas where necessary.
- The hamster was running on its exercise wheel. It felt completely healthy again. [because]
_________________________________________________________________________________ - The veterinarian examined the little animal. He found a small wound on its front leg. [when]
_________________________________________________________________________________ - Andrea tried her best to administer the liquid medicine. A lot of it spilled on the floor. [although]
_________________________________________________________________________________ - You must clean the hamster cage thoroughly. The pet will stay safe from diseases. [so that]
_________________________________________________________________________________ - The little pet perked up. It received the proper medical injection. [after]
_________________________________________________________________________________ - We cannot leave the animal clinic. The doctor tells us it is completely safe to go. [until]
_________________________________________________________________________________
? Click to see Answer Key & Explanation (Đáp án & Giải thích)
1: The hamster was running on its exercise wheel because it felt completely healthy again. Connects action to cause directly without a comma. (Nối trực tiếp hành động với nguyên nhân mà không cần dấu phẩy).
2: When the veterinarian examined the little animal, he found a small wound on its front leg. (Or: The veterinarian found a small wound on its front leg when he examined the little animal.) If ‘When’ starts, a comma is required. (Nếu ‘When’ đứng đầu thì bắt buộc phải có dấu phẩy ở giữa).
3: Although Andrea tried her best to administer the liquid medicine, a lot of it spilled on the floor. (Or: A lot of it spilled on the floor although Andrea tried her best to administer the liquid medicine.) Ensures contrast is logically connected. (Đảm bảo mối quan hệ tương phản được kết nối hợp lý).
4: You must clean the hamster cage thoroughly so that the pet will stay safe from diseases. ‘So that’ indicates a clear purpose, positioned in the middle. (‘So that’ chỉ mục đích rõ ràng, được đặt ở giữa câu).
5: The little pet perked up after it received the proper medical injection. (Or: After it received the proper medical injection, the little pet perked up.) Shows chronological sequence. (Biểu thị trình tự thời gian trước sau của hành động).
6: We cannot leave the animal clinic until the doctor tells us it is completely safe to go. ‘Until’ marks the time boundary line; no comma mid-sentence. (‘Until’ đánh dấu mốc thời gian giới hạn; không dùng dấu phẩy ở giữa).
