Cohesion across sentences
Cohesion emerges from controlled reference, lexical chains, substitution and logical connection across sentences, not from connectors alone.
01 · Concept foundation
Understand the terms before applying the rule
Each term below names a different grammatical object. Open examples and compare their function rather than memorising a Vietnamese translation alone.
lexical chain/ˈleksɪkəl tʃeɪn/
chuỗi từ vựngA sequence of semantically related words maintaining a topic across a text.
erosion → shoreline retreat → sediment loss
xói lở → bờ lùi → mất bùn cát
substitution/ˌsʌbstɪˈtjuːʃən/
phép thay thếReplacing a repeated structure with a pro-form such as one, do so or this.
The first model converged; the second one did not.
Mô hình thứ nhất hội tụ; mô hình thứ hai thì không.
coherent progression/kəʊˈhɪərənt prəˈɡreʃən/
tiến triển mạch lạcA sequence in which each sentence develops information made accessible by the previous context.
known information → new information
thông tin đã biết → thông tin mới
Complete lesson scope
Do not stop at one formula
Reference, substitution, ellipsis and lexical cohesion
Theme progression and given-new information
Tense, aspect and viewpoint across sentences
Paragraph chains and recoverable connections
Decision boundary: Cohesion markers should make existing logic visible; they cannot replace missing reasoning.
02 · Controlling rule
Cohesion is a network rather than a list of linkers. English texts maintain continuity through reference chains, substitution, ellipsis, lexical cohesion and given-to-new information flow. A pronoun must have a recoverable antecedent; a summary noun such as this limitation can classify a whole previous proposition; controlled repetition keeps the topic visible. Vietnamese can omit recoverable subjects more freely, whereas English normally requires an explicit subject and often needs a clearer reference chain.
given information/theme → reference or lexical link → new information/rhemeCohesion across sentences: build recoverable connections
Control reference, substitution, ellipsis, lexical chains and given-to-new information so that each sentence connects backward and moves the text forward.
Recoverable link → controlled repetition → new contribution
Cohesion is a surface network of grammatical and lexical ties. Coherence is the underlying logic. A text may contain many linkers yet remain incoherent if the reasoning is missing.
What exact noun, event or proposition does this sentence refer back to?
Should the writer repeat the key noun, use a pronoun, a demonstrative plus summary noun, or substitution?
Is the antecedent close enough and unambiguous?
What new information does the sentence add after the link is established?
1. Build explicit reference chains
Reference chains allow readers to track an entity across sentences without guessing. The form must preserve number, person and meaning.
full noun phrase → shorter noun phrase → pronoun/summary nounIntroduce a new entity with a full noun phrase before using a shorter reference.
Use it/they only when one plausible antecedent is available.
Use this/that plus a summary noun to classify a whole preceding idea: this trend, this limitation, this result.
The survey revealed a persistent data gap. This limitation increased uncertainty in the regional estimate.
Khảo sát cho thấy một khoảng trống dữ liệu kéo dài. Hạn chế này làm tăng độ bất định của ước lượng vùng.
This limitation summarizes and evaluates the previous proposition, creating both reference and interpretation.
Two models were tested. The process-based model reproduced the peak, whereas the statistical one underestimated it.
Hai mô hình được kiểm tra. Mô hình dựa trên quá trình tái hiện được đỉnh, trong khi mô hình thống kê đánh giá thấp nó.
One substitutes for model; it refers to the peak. Each reference has a clear antecedent.
Reference chain
a full noun phrase → the noun → it/they/this + summary nounMaintain an identifiable discourse entity.
A data gap was identified. This limitation affected calibration.
- Use a summary noun when the previous meaning is a whole proposition, not a simple object.
Substitution
count noun → one/ones | repeated action → do soAvoid unnecessary repetition while preserving recoverability.
The first sensor failed; the second one did not.
- Do not use one for uncountable nouns.
Lexical chain
technical term → related precise term → summary nounDevelop a topic through semantic relation.
shoreline retreat → erosion → sediment loss
- Precision is more important than avoiding every repetition.
Given-new progression
Sentence 1: A → B; Sentence 2: B → CCreate a readable information path.
The storm caused overtopping. This overtopping damaged the road.
- The repeated element should be meaningful, not merely grammatical.
Cohesion versus coherence
Many transition words, weak logic
Surface ties exist, but the reasoning does not progress.
Few explicit linkers, clear reference and reasoning
The paragraph can be coherent and cohesive through structure and reference.
Use cohesive devices to reveal logic, not to manufacture logic.
Pronoun versus summary noun
It affected the estimate.
It refers to one identifiable entity.
This limitation affected the estimate.
This limitation classifies a previous proposition as a limitation.
Use a summary noun when interpretation is needed, not only reference.
Precise repetition versus substitution
The sediment transport model... The model...
Repeating model preserves technical precision.
The first model... the second one...
One is efficient when the noun is clearly recoverable.
Do not sacrifice technical precision merely to avoid repetition.
Shared logic
Both languages use repetition, pronouns, demonstratives and lexical association to maintain topics.
Structural difference
Vietnamese can omit subjects and recover them from topic context more freely; standard English normally requires an explicit grammatical subject and clearer antecedents.
Transfer risk
Direct transfer can produce missing subjects, vague it/this, or repeated nouns without grammatical substitution.
Learning strategy
Make the English subject explicit, identify one antecedent, then choose repetition, pronoun, substitution or a summary noun according to meaning.
Conversation
- Prefer
- Use pronouns, demonstratives and repetition supported by shared context and intonation.
- Avoid
- Avoid dense summary nouns that sound bureaucratic in casual speech.
- Why
- Listeners can repair reference interactively, but ambiguity still needs control.
IELTS Speaking
- Prefer
- Extend answers through a clear chain: answer → reason → example → return to the question.
- Avoid
- Avoid disconnected lists of memorised sentences.
- Why
- Cohesion makes a longer answer easy to follow without sounding scripted.
IELTS Writing and technical prose
- Prefer
- Use explicit antecedents, summary nouns, controlled lexical repetition and given-new progression.
- Avoid
- Avoid vague this/it/they and arbitrary synonym replacement.
- Why
- Readers cannot ask for immediate clarification, so the text must carry its own reference system.
Cohesion choice console
Choose what must be carried from the previous sentence and inspect the most suitable device.
Select one discourse choice to inspect its effect.
Cohesive device inventory
Select by function and recoverability, not by a desire to avoid every repeated word.
| Device | Use | Example |
|---|---|---|
| Pronoun | Refer to one clear entity | The sensor failed. It was replaced. |
| Summary noun | Classify a previous proposition | The record was incomplete. This limitation... |
| Substitution | Replace recoverable repeated form | the first model; the second one |
| Lexical chain | Develop topic semantically | erosion → retreat → sediment loss |
Theme progression patterns
A paragraph can combine patterns; the purpose is readable progression, not rigid labeling.
| Pattern | Shape | Best use |
|---|---|---|
| Constant theme | A→B; A→C; A→D | Describe one entity from several angles |
| Linear progression | A→B; B→C; C→D | Explain a causal or procedural chain |
| Split theme | A→B+C; B→D; C→E | Develop two components introduced together |
✕ The model compared the survey with the simulation, and it was unreliable.
✓ The simulation was unreliable when compared with the survey.
It could refer to the model, survey, simulation or comparison; name the intended entity.
✕ The station failed during the storm. This affected the model.
✓ This data loss affected the model calibration.
This alone can refer to several aspects; a summary noun specifies the intended interpretation.
✕ The first information was reliable, but the second one was not.
✓ The first piece of information was reliable, but the second was not.
One substitutes for a countable noun; information is a mass noun unless packaged by a unit expression.
✕ The model was calibrated against two events. Public transport is important in cities.
✓ The model was calibrated against two events. This calibration reduced mean error in both periods.
The revised second sentence develops a recoverable topic instead of introducing an unrelated one.
Choose by communicative purpose and discourse effect
1. Which expression best summarizes an entire previous idea?
2. Which substitution is grammatical?
3. Which sequence shows linear progression?
4. What is the main problem with vague it?
Write a four-sentence IELTS paragraph in which sentence 2 uses a summary noun, sentence 3 uses controlled lexical repetition and sentence 4 completes a given-new chain.
Every pronoun has one clear antecedent.
Summary nouns accurately classify the previous idea.
Technical repetition preserves precision.
Each sentence adds new information.
No abrupt topic shift remains unexplained.
03 · Worked examples
Observe form, function and meaning together
The survey identified a persistent data gap. This limitation increased the uncertainty of the regional estimate.
Khảo sát xác định một khoảng trống dữ liệu kéo dài. Hạn chế này làm tăng độ bất định của ước lượng khu vực.
Three models were tested. The first reproduced the timing accurately; the other two underestimated the peak.
Ba mô hình được kiểm tra. Mô hình thứ nhất tái hiện thời điểm chính xác; hai mô hình còn lại đánh giá thấp đỉnh.
The northern stations showed a rapid increase. A similar pattern was observed in the central basin.
Các trạm phía bắc cho thấy mức tăng nhanh. Một mẫu tương tự được quan sát ở lưu vực trung tâm.
I used to live near the coast, so it is a place I still feel strongly connected to.
Tôi từng sống gần bờ biển nên đó vẫn là nơi tôi cảm thấy gắn bó sâu sắc.
04 · High-risk contrast
Explain why one form fails, not only which answer is correct
The model was compared with the observations. It was inaccurate, and this affected it.
The model was compared with the observations. Its peak estimate was inaccurate, and this error affected the flood map.
The original pronouns allow several possible antecedents. Replacing them with a precise noun phrase and a summary noun makes the reference chain recoverable and identifies what caused what.
05 · Mastery check
Apply the rule before marking the lesson complete
Which sentence is grammatically acceptable in the target system?
Which description best defines “lexical chain”?
Which example is one of the verified target patterns in this lesson?
Which structural formula belongs to this lesson?
Complete all four checks, then submit a sentence for target-form feedback.
06 · IELTS Academic
Transfer grammar into a real communicative task
In Speaking, reference lets you avoid unnatural repetition while keeping the answer easy to follow. In Writing Task 1, use this figure, this trend, the former and the latter only when their referents are unmistakable. In Task 2, summary nouns such as this concern, this assumption and this approach connect an argument more naturally than repeated sentence-initial linkers.
Build an unambiguous reference chain across at least three sentences.
Use one/ones, do so or ellipsis only when the omitted material is structurally recoverable.
Move from given to new information without repeating every noun or changing topic abruptly.
Explain why English often needs an explicit subject where Vietnamese can omit one.