Introduction: Making Sense of Expository and Problem-Solution Writing
Welcome! Writing in English at the Upper Secondary level (ม.4–6) is all about expressing your thoughts clearly, logically, and purposefully. While narrative writing focuses on telling stories and opinion writing centers on personal viewpoints, expository writing and problem-solution writing focus on explaining reality, sharing useful information, and solving real-world challenges.
Don't worry if this seems challenging at first. Once you learn the basic building blocks—how to organise your paragraphs, connect your ideas, and use key grammar patterns like modals and conditional sentences—you will find that writing structured texts is straightforward and manageable.
Note: For foundational paragraph architecture (topic sentences and supporting details), please refer to the chapter on Paragraph writing.
Key Takeaway: Expository writing explains facts and processes objectively, while problem-solution writing identifies an issue and provides practical steps to fix it.
Part 1: What is Expository Writing?
The word expository comes from expose, which means to reveal, show, or explain. In expository writing, your goal is to inform the reader about a specific topic using facts, reasons, and clear descriptions rather than personal emotional stories.
Common Types of Expository Writing
In your English studies, you will encounter three common expository styles:
1. Descriptive / Informative Explanation: Explaining what something is, what it consists of, or how it works (e.g., explaining how a solar panel generates power or what a balanced diet contains).
2. Process Explanation: Explaining how to do something step by step (e.g., how to search for reliable study materials online or how to separate household waste).
3. Cause and Effect Explanation: Explaining why something happens and what happens as a result (e.g., why air pollution rises during winter months).
Structure of an Expository Text
A good expository text usually follows a clean, three-part structure:
• Introduction: Introduces the topic clearly and provides a main statement showing what will be explained.
• Body Paragraph(s): Presents facts, logical steps, or reasons. Each paragraph focuses on one clear sub-point supported by details.
• Conclusion: Summarises the main points briefly without introducing completely new topics.
Did you know? Expository writing is the most common style of writing found in textbooks, science magazines, news reports, and instructional guides worldwide.
Key Takeaway: Keep expository writing objective, organized, and focused on facts and clear steps.
Part 2: What is Problem-Solution Writing?
Problem-solution writing is a specific kind of writing where you examine an issue (a difficulty, danger, or unwanted situation) and propose workable actions to solve or improve it. It connects closely with everyday topics such as school life, the environment, health, and technology.
The Two Main Building Blocks
Every problem-solution text has two core components:
• The Problem: What is the issue? Why does it happen? Who is affected? Why is it serious?
• The Solution: What specific actions can be taken? Who should take these actions? What will happen if these solutions are applied?
Two Ways to Organise Your Writing
You can organize your paragraphs in one of two ways:
Pattern A: The Block Pattern (Best for Beginners)
• Paragraph 1: Introduction — State the problem clearly and explain why it matters.
• Paragraph 2: The Problem & Causes — Explain the background, causes, and effects of the problem in full.
• Paragraph 3: The Solutions — Propose two or three practical solutions and explain how they will work.
• Paragraph 4: Conclusion — Summarise the solutions and leave a hopeful concluding thought.
Pattern B: The Chain Pattern (Point-by-Point)
• Paragraph 1: Introduction — Introduce the overall issue.
• Paragraph 2: Problem 1 + Solution 1 — Discuss the first cause/difficulty and immediately present its specific remedy.
• Paragraph 3: Problem 2 + Solution 2 — Discuss the second cause/difficulty and its specific remedy.
• Paragraph 4: Conclusion — Summarise both points and give a final evaluation.
Key Takeaway: Choose either the Block Pattern or the Chain Pattern before you begin writing so your ideas do not become tangled.
Part 3: Essential Connectives & Transitions
To guide your reader smoothly from one sentence to the next, you need linking words. The syllabus highlights several categories of connectives that are essential for expository and problem-solution tasks.
1. Sequencing Connectives (Ordering Steps & Solutions)
Use these when explaining steps in a process or introducing multiple solutions one after another:
• First, Second, Third, Fourth
• Next, Then, Finally
Example: First, students should separate recyclable plastic bottles. Next, these bottles can be collected by the school eco-club. Finally, they are sent to a recycling facility.
2. Cause and Effect Connectives
These show why a problem occurs or what results from an action:
• because + subject + verb (clause)
Example: Air quality worsens because people burn crop waste in open fields.
• because of / due to / owing to + noun phrase
Example: Traffic congestion occurs due to the heavy rain.
Example: The river became polluted owing to chemical waste from nearby factories.
• caused by
Example: Many health issues among teenagers are caused by lack of sleep.
• so (conjunction linking cause to result)
Example: Many students skip breakfast, so they feel tired during morning classes.
• so…that / such…that (expressing degree leading to a result)
Example: The classroom was so noisy that the teacher could not continue the lesson.
Example: It was such a serious storm that several roads were flooded.
3. Contrast and Concession Connectives
Use these when showing two sides of a situation, difficulties in solving an issue, or balancing arguments:
• however (often followed by a comma)
Example: Solar power is clean and renewable. However, solar panels can be expensive to install.
• although + clause
Example: Although public transport is cheap, it is often crowded during rush hours.
• in spite of + noun phrase
Example: In spite of the clear warning signs, some people still litter in the park.
• on the other hand
Example: Private cars offer convenience. On the other hand, they create severe air pollution.
• not only…but also / both…and / as well as (adding complementary points)
Example: Planting trees not only reduces urban heat but also improves air quality.
Example: We need both strict school rules and student cooperation to solve this issue.
Key Takeaway: Always check what follows your connective: because takes a full subject-verb clause, whereas due to, because of, and in spite of are followed by nouns or noun phrases.
Part 4: Key Grammar for Proposing Solutions
When presenting recommendations and solutions, specific grammatical tools allow you to vary your tone from polite advice to strong necessity.
1. Modal Verbs for Recommendations and Obligations
Modal verbs are followed by a bare infinitive (the base form of the verb without to, except for ought to and have to).
• should / ought to (advice, good recommendations):
Example: Teenagers should exercise for at least 30 minutes every day.
Example: We ought to save water by turning off the tap while brushing our teeth.
• need to / have to / must (strong necessity or obligation):
Example: The community needs to establish a clear waste disposal schedule.
Example: Motorcyclists must wear helmets to prevent head injuries.
2. Active vs. Passive Voice with Modals
In problem-solution writing, the action itself is often more important than the person doing it. Using the passive voice gives your writing a formal, objective tone:
• Active Structure: Modal + base verb
Example: The government must improve public transport.
• Passive Structure: Modal + be + past participle (V.3)
Example: Public transport must be improved.
Example: Food waste should be reduced in school canteens.
Example: Old computers ought to be recycled properly.
3. Conditional Sentences (If Clauses) for Predicting Results
Conditional sentences allow you to explain what positive outcomes will happen when your solution is carried out:
• Structure: If + Present Simple, Future Simple (will + base verb)
Example: If students bring reusable water bottles, the amount of single-use plastic waste will decrease rapidly.
Example: The school will save electricity if everyone turns off air conditioners when leaving the room.
4. Expressing Limits: too…to and enough to
• too + adjective + to-infinitive (shows an excessive quality that prevents an action):
Example: The river water was too dirty to drink.
• adjective + enough + to-infinitive (shows sufficient quality to achieve something):
Example: The new bins are large enough to hold all the classroom waste.
Key Takeaway: Combine modal verbs (should be done) with conditional sentences (if we do this, that will happen) to propose strong, convincing solutions.
Part 5: Annotated Model Texts
Model 1: Expository Writing (Process & Explanation)
Topic: How Composting Works
[Introduction] Composting is an effective natural process that turns organic household waste into rich fertilizer for plants and crops.
[Body Paragraph 1 - Steps] The process consists of three simple stages. First, organic materials such as vegetable peels, fruit skins, and dried leaves are collected. Second, these materials are layered in an outdoor container with soil and water. Next, tiny bacteria and insects break down the green waste over several weeks. Finally, the mixture turns into dark, nutrient-rich soil that can be used in home gardens.
[Body Paragraph 2 - Benefits] Composting is valuable because it reduces the volume of garbage sent to city landfills. Furthermore, chemical fertilizers are not needed because of the natural nutrients present in composted soil.
[Conclusion] In conclusion, composting is an easy and environmentally friendly way to turn everyday food scraps into a valuable resource.
Model 2: Problem-Solution Writing (Block Pattern)
Topic: Managing Exam Stress Among Upper Secondary Students
[Introduction] In many high schools, senior students experience severe stress and anxiety during midterm and final examination periods. If this issue is not addressed, it can harm both their physical health and academic performance.
[The Problem & Causes] This widespread stress is mainly caused by heavy homework loads, tight deadlines, and high expectations from family members. Because students spend late nights studying, they often do not get enough sleep. Consequently, some teenagers become so exhausted that they cannot concentrate during lessons. Although studying hard is necessary, constant worry makes learning ineffective.
[The Solutions] To resolve this problem, several practical measures should be introduced. First, schools ought to provide guidance sessions on time management and relaxation techniques. Second, teachers need to coordinate assignment due dates so that projects do not pile up in the same week. Finally, students themselves must maintain a healthy routine. If students sleep at least seven hours each night and take regular short breaks, their memory and concentration will improve significantly.
[Conclusion] In summary, while exam stress is a serious problem for secondary students, it can be managed through balanced study schedules and cooperation between teachers and learners.
Key Takeaway: Notice how both models use clear topic sentences, sequencing markers (First, Second, Finally), cause/effect links (because, caused by), and modal passives (should be introduced).
Part 6: Common Mistakes to Avoid
Review this checklist to make sure your writing stays accurate and polished:
• Mistake 1: Confusing "because" with "because of / due to"
Incorrect: Many students fail because of they do not revise.
Correct: Many students fail because they do not revise. (clause)
Correct: Many students fail due to poor preparation. (noun phrase)
• Mistake 2: Missing "be" in passive modal constructions
Incorrect: Plastic pollution must reduce immediately.
Correct: Plastic pollution must be reduced immediately.
• Mistake 3: Using "to" after standard modal verbs
Incorrect: The school should to buy more recycling bins.
Correct: The school should buy more recycling bins. (Remember: use base verb after should, must, can; use to only with ought to and have to / need to).
• Mistake 4: Presenting only problems without actionable solutions
In a problem-solution paper, balance is critical. If your essay has two paragraphs about the disaster, make sure you dedicate an equal amount of space explaining concrete steps to resolve it.
• Mistake 5: Complicating vocabulary unnecessarily
At CEFR B1 level, clear, grammatically correct sentences using compound and complex structures are much better than long, confusing sentences filled with misplaced words.
Quick Review & Self-Check Checklist
Before submitting your expository or problem-solution composition, ask yourself:
• Did I clearly introduce the topic or problem in my first paragraph?
• Did I organize my body paragraphs logically (Block or Chain pattern)?
• Did I use accurate sequencing words (First, Next, Then, Finally)?
• Did I link causes and results correctly (because, due to, so…that)?
• Did I suggest realistic solutions using modals (should, ought to, must, need to)?
• Did I apply correct passive structures when focusing on actions (should be cleaned, must be solved)?
• Did I write a brief conclusion that wraps up the whole text?