Conjunctions — Liên từ

Tóm tắt

Liên từ (Conjunction) là từ dùng để nối các thành phần trong câu — từ với từ, cụm từ với cụm từ, mệnh đề với mệnh đề. Không có liên từ, ta chỉ có thể viết những câu đơn ngắn, rời rạc.

• I like coffee and tea.
• She was tired but she kept studying.
• He stayed home because it was raining.

Tại sao quan trọng

Liên từ là chìa khóa để tạo câu ghép (compound) và câu phức (complex). Trong IELTS, dùng đa dạng liên từ thể hiện khả năng sử dụng Grammatical Range and Accuracy, giúp điểm Writing và Speaking tốt hơn.

Loại 1: Coordinating Conjunctions — Liên từ kết hợp

Nối hai thành phần ngang hàng (cùng loại: từ + từ, hoặc mệnh đề độc lập + mệnh đề độc lập):

Từ gợi nhớ: FANBOYS

Liên từ	Nghĩa	Ví dụ
For	vì (lý do — khá trang trọng)	She left early, for she had a meeting.
And	và	I like coffee and tea.
Nor	cũng không	He doesn't smoke, nor does he drink.
But	nhưng	She's young but experienced.
Or	hoặc	You can walk or take a taxi.
Yet	nhưng (dù vậy)	It was expensive, yet worth it.
So	vì vậy	It rained, so we stayed inside.

Quan trọng: Khi nối hai mệnh đề độc lập, đặt dấu phẩy trước coordinating conjunction: - I was hungry, so I made a sandwich. ✅ - I was hungry so I made a sandwich. ✅ (cũng chấp nhận được) - I was hungry so, I made a sandwich. ❌

Loại 2: Subordinating Conjunctions — Liên từ phụ

Nối mệnh đề phụ (subordinate clause) với mệnh đề chính. Mệnh đề phụ không đứng một mình được — nó phụ thuộc vào mệnh đề chính.

Chỉ Nguyên nhân / Lý do

Liên từ	Ví dụ
because	She stayed home because she was sick.
since	Since it was raining, we cancelled the trip.
as	As the traffic was heavy, I was late.

Chỉ Sự tương phản / Nhượng bộ

Liên từ	Ví dụ
although / though / even though	Although it was cold, she wore a T-shirt.
while	While some people prefer cities, others prefer rural life.
whereas	He likes jazz, whereas his sister prefers pop.

Phân biệt: "although" và "despite/in spite of" diễn đạt cùng ý, nhưng: - although + mệnh đề (S + V): Although it was cold... - despite / in spite of + cụm danh từ: Despite the cold weather...

Chỉ Điều kiện

Liên từ	Ví dụ
if	If you study hard, you will pass.
unless	Unless you hurry, you'll be late. (= if not)
provided / as long as	As long as you practise daily, you'll improve.
in case	Take an umbrella in case it rains.

Chỉ Thời gian

Liên từ	Ví dụ
when	Call me when you arrive.
while	She studied while I cooked dinner.
before / after	Brush your teeth before you go to bed.
until / till	Wait until I get back.
as soon as	I'll call you as soon as I know.
since	I've lived here since I was a child.
once	Once you understand the grammar, it becomes easier.

Chỉ Mục đích

Liên từ	Ví dụ
so that	She practised daily so that she could improve.
in order that	He saved money in order that he could travel.

Chỉ Kết quả

Liên từ	Ví dụ
so...that	It was so cold that we couldn't go out.
such...that	It was such a cold day that we stayed inside.

Vị trí của mệnh đề phụ

Mệnh đề phụ có thể đứng trước hoặc sau mệnh đề chính:

• Because it was raining, we stayed inside. ✅ (đứng đầu → có dấu phẩy)
• We stayed inside because it was raining. ✅ (đứng sau → không cần dấu phẩy)

Loại 3: Correlative Conjunctions — Cặp liên từ tương quan

Hai liên từ đi cặp với nhau:

Cặp	Nghĩa	Ví dụ
both...and	cả...lẫn	She speaks both English and French.
either...or	hoặc...hoặc	You can use either a pen or a pencil.
neither...nor	không...cũng không	He speaks neither Chinese nor Japanese.
not only...but also	không chỉ...mà còn	She's not only smart but also hardworking.
whether...or	dù...hay	Whether you like it or not, you must attend.

Quan trọng về chia số: Với "either...or" và "neither...nor", chia động từ theo chủ ngữ gần nhất: - Either the teacher or the students are responsible. (students → are) - Neither the students nor the teacher is here. (teacher → is)

Lỗi thường gặp

Lỗi 1: Dùng "although" và "but" cùng lúc

• ❌ Although he was tired, but he kept working.
• ✅ Although he was tired, he kept working.
• ✅ He was tired, but he kept working.
• Tại sao: Một câu chỉ cần một liên từ tương phản. Dùng cả hai là thừa.

Lỗi 2: Dùng "because" và "so" cùng lúc

• ❌ Because it was raining, so we stayed inside.
• ✅ Because it was raining, we stayed inside.
• ✅ It was raining, so we stayed inside.

Lỗi 3: Câu mảnh (Fragment) — mệnh đề phụ đứng một mình

• ❌ Although she was tired. (không có mệnh đề chính)
• ✅ Although she was tired, she finished the work.
• ❌ Because I like music.
• ✅ Because I like music, I practise every day.

Lỗi 4: Nhầm "despite" với "although"

• ❌ Despite she was tired, she kept going.
• ✅ Despite being tired, she kept going. (despite + -ing)
• ✅ Despite her tiredness, she kept going. (despite + danh từ)
• ✅ Although she was tired, she kept going. (although + mệnh đề)

Lỗi 5: Nhầm "so" (vì vậy) và "so that" (để)

• ❌ She studied hard so she could pass. → nghĩa không rõ
• ✅ She studied hard so that she could pass. (mục đích → so that)
• ✅ She studied hard, so she passed. (kết quả → so)

Ứng dụng trong IELTS

Nối ý kiến trong Writing Task 2:

Thêm ý: - Education is important, and it gives people opportunities to succeed. - Not only does education improve career prospects, but it also develops critical thinking.

Tương phản: - Although technology has many benefits, it also has drawbacks. - Some people prefer city life, whereas others value the peace of rural areas.

Nguyên nhân: - Many young people move to cities because they are looking for better job opportunities. - Since the internet became widely available, people's lives have changed dramatically.

Điều kiện: - If governments invested more in education, inequality would decrease. - Urbanisation will continue unless rural areas receive more support.

Trong IELTS Speaking:

• I enjoy travelling and learning about different cultures.
• Although I was nervous at first, I gradually became more confident.
• I chose this career because I've always been passionate about it.

Bài tập luyện

Điền liên từ phù hợp

1. She was cold, ___ she put on a coat. (kết quả)
2. ___ he studied hard, he failed the exam. (tương phản)
3. You'll miss the bus ___ you leave now. (điều kiện)
4. I haven't spoken to her ___ we graduated. (thời gian)
5. She bought a dictionary ___ she could look up words easily. (mục đích)

Sửa lỗi

1. Although it was a long journey, but we enjoyed it.
2. Because he was late, so the teacher was angry.
3. Despite she had a headache, she went to work.
4. He's not only intelligent but also works hard.
5. I'll call you when I will arrive.

Đáp án

Điền liên từ: 1. so | 2. Although / Even though | 3. unless / if you don't | 4. since | 5. so that

Sửa lỗi: 1. Although it was a long journey, we enjoyed it. (bỏ "but") 2. Because he was late, the teacher was angry. (bỏ "so") — hoặc: He was late, so the teacher was angry. (bỏ "because") 3. Despite having a headache, she went to work. — hoặc: Although she had a headache... 4. He's not only intelligent but also hardworking. (not only...but also + cùng cấu trúc ngữ pháp) 5. I'll call you when I arrive. (sau when chỉ thời gian → hiện tại, không phải tương lai)

Tóm tắt nhanh

Coordinating (FANBOYS): for, and, nor, but, or, yet, so — nối hai thành phần ngang hàng

Subordinating: nối mệnh đề phụ với mệnh đề chính - Nguyên nhân: because, since, as - Tương phản: although, though, even though, while, whereas - Điều kiện: if, unless, provided, as long as - Thời gian: when, while, before, after, until, as soon as, since

Correlative: both...and | either...or | neither...nor | not only...but also

Bẫy phổ biến: - Không dùng "although" + "but" cùng lúc - Không dùng "because" + "so" cùng lúc - Mệnh đề phụ không đứng một mình - despite + noun/-ing (không + mệnh đề) - Sau when/if (chỉ thời gian tương lai) → dùng present simple