Grammar and vocabulary for writing - Punctuation essentials

Learning Outcomes

By the end of this article, you will be able to apply key punctuation rules to improve accuracy and clarity in IELTS Writing. You will know how to use full stops, commas, and apostrophes correctly, recognize typical errors in sentence boundaries, and edit your writing for basic punctuation mistakes under exam conditions.

IELTS Academic, General & UKVI Syllabus

For IELTS, you are required to understand and use essential punctuation accurately in your written responses. For revision, focus on these syllabus points:

• Use full stops to mark the end of sentences and avoid sentence run-ons.
• Insert commas in lists and after introductory phrases, and avoid comma splices.
• Apply apostrophes correctly for contractions and possession.
• Recognize basic punctuation errors and edit them out to clarify meaning.
• Ensure correct capitalization to start sentences and for proper nouns.
• Write in complete sentences, not sentence fragments.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. What is the main purpose of a full stop in English writing?
2. Give two correct uses of a comma in IELTS Writing Task 2.
3. When is an apostrophe used in IELTS Academic writing?
4. True or false: "The students books’ are on the desks" contains a punctuation error.

Introduction

Punctuation is essential for accurate and clear IELTS Writing answers. Incorrect punctuation can cause confusion, create sentence fragments, or turn correct grammar into errors. Using the right punctuation improves not only your band score for grammatical range and accuracy but also makes your writing concise and easy to read, especially under exam conditions.

Key Term: Punctuation
The set of marks, such as full stops and commas, used in writing to clarify meaning and separate sentences, phrases, or words.

Full Stops: Marking the End of a Sentence

A full stop (.) shows where one sentence ends and the next starts. If you do not use full stops, your writing can become a run-on sentence, which is likely to lose you marks.

• Start every sentence with a capital letter.
• Put a full stop at the end of every main statement.
• Avoid linking two complete sentences with only a comma.

Key Term: Run-on Sentence
A sentence in which two or more main clauses are joined without proper punctuation or connecting words.

Worked Example 1.1

An IELTS candidate wrote:

Global warming is a serious challenge it may damage agriculture and human health this century.

Question: What punctuation error is there? How would you correct it?

Answer:
Two sentences are run together with no full stop. It should be:
Global warming is a serious challenge. It may damage agriculture and human health this century.

Exam Warning

Omitting full stops between your sentences causes confusion and lowers your score for sentence structure. Always reread your answer to check for missing full stops after each complete idea.

Commas: Organizing Ideas Clearly

Commas (,) help separate ideas within sentences, but they do not end sentences. Use a comma to separate items in a list, after introductory phrases, or to set off extra information within a sentence.

• Use commas between the items in a sequence: "Education, health, and transport are essential."
• Add a comma after most introductory words or phrases: "However, some people disagree."
• Commas do NOT join two complete sentences. Use a full stop or a joining word (such as 'and' or 'but') instead.

Key Term: Comma Splice
The error of joining two sentences with only a comma, without a connecting word.

Worked Example 1.2

Consider this sentence:

University is important, it allows students to gain valuable skills.

Question: Is this comma used correctly? If not, correct the error.

Answer:
The comma is used incorrectly to join two sentences (comma splice). Instead, use a full stop or a connector:
University is important. It allows students to gain valuable skills.
or
University is important, as it allows students to gain valuable skills.

Apostrophes: Showing Possession and Contractions

Apostrophes (') are used for two purposes in IELTS Writing:

1. To show possession (ownership).
2. To indicate contractions (words made shorter, such as "can't" instead of "cannot"), though contractions should generally be avoided in Academic Writing.

• For one owner: "the student's essay" (one student).
• For more than one: "the students' essays" (several students).
• Do not use apostrophes for regular plurals ("essays" not "essay's").

Key Term: Apostrophe
A punctuation mark used to show possession or to replace missing letters in contractions.

Worked Example 1.3

Identify and correct the error in this sentence:

Many students struggles with its use, the rule’s are confusing.

Answer:
The word "rule's" is incorrect. It should be "rules" (simple plural). The apostrophe is not needed.
Correct version: Many students struggle with its use; the rules are confusing.

Key Term: Contraction
A shorter form of a word or group of words, made by leaving out letters and replacing them with an apostrophe.

Key Term: Possessive Apostrophe
The use of an apostrophe to show ownership, e.g., "students' opinions."

Capital Letters and Sentence Boundaries

Use a capital letter:

• At the start of every sentence.
• For proper nouns (names of people, countries, organizations).

Check that every capital letter begins a sentence or proper noun—not random words in the middle of sentences.

Common Errors and How to Fix Them

• Missing Full Stops: Sentences run together with no separation.
• Comma Splices: Two full sentences joined with only a comma.
• Apostrophe Mistakes: Using apostrophes for plurals, or omitting them in possessives.
• Lack of Capitalization: Not capitalizing "i" (the pronoun) or names.

Revision Tip

In the IELTS exam, leave time at the end of your writing to quickly scan for missing full stops, random commas, and misused apostrophes.

Worked Example 1.4

Rewrite this sentence correctly:

these factors are important however they are not the only considerations

Answer:
These factors are important. However, they are not the only considerations.

Summary

Punctuation marks like full stops, commas, and apostrophes control where your sentences begin and end, group your ideas logically, and show ownership or missing letters. Errors in these marks can turn clear writing into confusion. Learning and practising these basics will clarify your writing and help you achieve a higher IELTS score.

Key Point Checklist

This article has covered the following key knowledge points:

• Use full stops to clearly end every complete sentence.
• Start every new sentence with a capital letter.
• Use commas for lists, after introductory phrases, and around extra information—not to join sentences.
• Avoid comma splices by using a full stop or connector.
• Use apostrophes only for possession (in nouns) or, when appropriate, in contractions.
• Ensure all proper nouns and "I" are capitalized.
• Edit your writing to remove basic punctuation errors before finishing.

Key Terms and Concepts

• Punctuation
• Run-on Sentence
• Comma Splice
• Apostrophe
• Contraction
• Possessive Apostrophe