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Sentence Completion in IELTS Reading: Word Limits, Exact Words

IELTS Reading29 August 2026 · 7 min read · WiderAI Team

Sentence completion in IELTS Reading gives you an unfinished sentence and asks you to complete it using words taken directly from the passage. Two rules decide almost everything: you must stay inside the stated word limit (usually "NO MORE THAN TWO WORDS" or "NO MORE THAN THREE WORDS AND/OR A NUMBER"), and the words you write must appear in the passage exactly as they are printed there. Change the form of a word, add an extra word, or misspell what you copy, and the answer is marked wrong — even if your meaning is perfect.

The good news is that this makes sentence completion one of the most learnable question types in the test. The sentence on the question paper is a paraphrase of one specific part of the passage. Your job is to find that part, identify the words that fit the gap grammatically, and copy them with total accuracy. There is no interpretation, no opinion, and no trick beyond careful reading.

For sentence completion, the answers also follow the order of the passage. The answer to question 2 comes after the answer to question 1 in the text. That single fact turns a 900-word passage into a series of short, manageable search zones.

What does the word limit actually mean?

The instruction line above the questions is part of the test, and IELTS enforces it mechanically. If the limit is "no more than two words" and the correct idea needs the phrase the industrial revolution, the answer key will accept industrial revolution — the examiners choose gaps so that a correct answer always fits the limit. If you write three words where two are allowed, the answer is wrong regardless of content.

A few details candidates regularly get wrong:

• A hyphenated word such as well-being or twentieth-century counts as one word.
• "AND/OR A NUMBER" means a number is allowed in addition to the words. A number written in figures (1969, 25%) counts as a number, not a word.
• Articles count. The mineral deposits is three words; mineral deposits is two. If the sentence already ends in the, do not write it again.
• Contractions are best avoided entirely — you will never need one, because you are copying from an academic passage.

Why must you use the exact words from the passage?

Sentence completion tests whether you can locate specific information and recognise how the question sentence paraphrases the passage. It does not test your ability to reword ideas — that is what Writing does. So the marking is binary: the words in the official answer key come straight from the text, and anything else fails.

This means synonyms are wrong even when they are accurate. If the passage says rapid urban expansion and you write fast city growth, you have understood perfectly and scored zero. It also means grammar is a free checking tool. The completed sentence must read as correct English, so if the gap follows a, the answer starts with a consonant-sounding singular noun; if the gap follows have been, you need a past participle or an adjective. When your candidate answer breaks the grammar of the sentence, you have copied the wrong words — go back to the text.

Spelling is copied, not remembered. The word is sitting in front of you in the passage, so a spelling mistake here is pure carelessness, and it still costs the whole mark. Transfer answers letter by letter, especially for technical or unfamiliar vocabulary, which is exactly what these gaps tend to target.

What is a reliable method for sentence completion?

1. Read the instruction and fix the word limit in your mind.
2. Read the incomplete sentence and decide what kind of word the gap needs — a noun, a number, an adjective plus noun, a person, a place. Say it to yourself: "I am looking for a material" or "I need a two-word noun phrase."
3. Underline the content words in the question sentence that are likely to be paraphrased: names, dates, and technical terms usually survive unchanged; verbs and descriptive words usually appear as synonyms.
4. Scan the passage for that zone, remembering that answers come in passage order, so start from wherever the previous answer was found.
5. Read the located sentence slowly, choose the exact words, and check them against the gap's grammar and the word limit before writing.

The order rule deserves emphasis because it also rescues you when one question is stubborn. If you cannot find the answer to question 4 but you have found 3 and 5, the answer to 4 sits in the text between them. Search that strip only, and if it still will not appear, write your best guess and move on — there is no penalty for a wrong answer in IELTS Reading.

Which mistakes cost the most marks?

Across thousands of practice tests, the same errors repeat:

• Answering from memory or logic instead of the text. The sentence looks completable from general knowledge, so candidates write a plausible word that is not in the passage. Every answer must be findable on the page.
• Copying too much. Nervous candidates add a safety word — an adjective, an article — and break the limit. Copy the minimum that completes the meaning.
• Ignoring the grammar of the completed sentence. If your answer produces the process are controlled, it is wrong, and the error was detectable in five seconds.
• Searching for the question's exact words in the passage. The sentence stem is a paraphrase. Hunt for the idea and the anchor words (names, numbers, capitalised terms), not the stem word for word.
• Losing the order. Jumping randomly around the passage wastes minutes. Work forward through the text with the questions.

How is sentence completion different from similar question types?

IELTS Reading also uses summary, note, table and flow-chart completion, and the same two rules — word limit, exact words — govern all of them, so the method above transfers directly. The one relative worth separating is matching sentence endings, where you finish a sentence by choosing from a printed list of endings (A, B, C…) rather than copying from the passage. There, the word limit is irrelevant and the skill is matching meaning. Check whether the question gives you a box of options or a blank line: a blank line means passage words, a box means selection.

If reading is only one of the papers you are polishing, the same disciplined, criteria-first approach applies elsewhere — see how examiners think in our guide to speaking band descriptors explained, or browse the WiderAI blog for the other question types.