Sentence correction looks like it tests everything. Open any exam paper or grammar exercise and you will find questions on tenses, pronouns, prepositions, articles, comparisons and word choice, apparently at random.
In practice it does not test everything. The same small set of errors comes up again and again, because those are the mistakes people actually make. Learn to recognise twelve patterns and you will handle the large majority of questions you meet, whether you are sitting a competitive exam, editing your own writing, or simply trying to stop making the same slips.
This guide covers those twelve rules with wrong-and-right examples, then gives you a practice set with full explanations.
How to Approach a Sentence Correction Question
Before the rules, a method. Most people read the sentence, feel that something is odd, and guess. That works about half the time. This is better:
1. Read the whole sentence first. Do not stop at the first thing that sounds strange. Errors often sit at the end, and some sentences are correct as they stand.
2. Find the subject and the main verb. Strip out the descriptive parts. The list of items you requested last week __ on my desk. The subject is list, not items, so the verb is is. Most agreement errors dissolve the moment you do this.
3. Check the error families in order. Agreement, then tense, then pronouns, then modifiers, then parallelism. This is roughly the order of frequency.
4. Trust structure over sound. “It sounds right” is unreliable, because what sounds right is usually whatever you hear most often, which may itself be wrong. If you can name the rule, you can be confident in the answer.
Family One: Agreement
Rule 1: The Verb Agrees with the Subject, Not with the Nearest Noun
This is the most tested error in English, and it is almost always caused by words sitting between the subject and the verb.
| Wrong | Right |
|---|---|
| The quality of the products are poor. | The quality of the products is poor. |
| A box of chocolates were left on the table. | A box of chocolates was left on the table. |
| Each of the students have submitted the form. | Each of the students has submitted the form. |
The trick is to delete the phrase between the subject and the verb. The quality of the products is poor. The error becomes obvious.
Words that always take a singular verb: each, every, either, neither, one of, everyone, everybody, someone, nobody, anything, none (in careful usage).
Watch these too:
- Either the manager or the assistants are attending. With either/or and neither/nor, the verb matches the nearer subject.
- Ten pounds is too much for a sandwich. Amounts, distances and periods of time take a singular verb when treated as a single unit.
- The news is on at six. Some nouns look plural but are singular: news, mathematics, physics, economics.
Rule 2: A Pronoun Must Match What It Refers To
The pronoun must agree in number, and it must be clear what it points to.
| Wrong | Right |
|---|---|
| Every student must bring their own ID. (formal writing) | Every student must bring his or her own ID. |
| The company announced their results. | The company announced its results. |
| Neither of the boys had done their homework. | Neither of the boys had done his homework. |
A note on their with singular subjects: in ordinary spoken and modern written English, Every student must bring their own ID is widely accepted and increasingly standard. Formal exams often still mark it wrong, so know both positions and answer according to the context you are in.
Unclear reference is the second half of this rule:
When Sarah spoke to Priya, she was upset. Who was upset? Rewrite: Sarah was upset when she spoke to Priya.
Family Two: Time
Rule 3: Keep Your Tenses Consistent
Within a sentence, do not switch time frames without a reason.
| Wrong | Right |
|---|---|
| He opened the door and sees a parcel. | He opened the door and saw a parcel. |
| She said that she will come tomorrow. | She said that she would come the next day. |
That second example is the sequence of tenses rule: when the reporting verb is in the past, the reported verb usually shifts back too. Will becomes would, is becomes was, has done becomes had done.
The exception is a general truth: The teacher said that water boils at 100 degrees stays in the present.
Rule 4: Match the Tense to Its Time Marker
Certain time expressions demand certain tenses. This is one of the easiest rules to apply once you know it.
| Marker | Tense required | Example |
|---|---|---|
| yesterday, last week, in 2019, ago | past simple | I met him last week. |
| since, for, already, yet, just, ever, never | present perfect | I have known her since 2019. |
| when + past action | past simple / past continuous | I was cooking when he called. |
| by + future time | future perfect | I will have finished by Friday. |
The classic error: I have finished it yesterday. Because yesterday is a finished time, it must be I finished it yesterday.
Rule 5: Get Conditionals Right
Three patterns cover almost everything, and the mistake is nearly always mixing them.
| Type | Structure | Example |
|---|---|---|
| First (real future) | If + present, will + verb | If it rains, we will cancel. |
| Second (unreal present) | If + past, would + verb | If I had more time, I would learn Spanish. |
| Third (unreal past) | If + past perfect, would have + V3 | If I had known, I would have told you. |
Never write if I would have. The would belongs in the other half of the sentence: If I had known, I would have told you.
Also note If I were you, not If I was you, in the second conditional.
Family Three: Position and Balance
Rule 6: Put Modifiers Next to What They Modify
A descriptive phrase attaches itself to whatever noun sits closest. Put it in the wrong place and the sentence says something you did not mean.
| Wrong | Right |
|---|---|
| Running for the bus, my bag fell open. | Running for the bus, I felt my bag fall open. |
| She served sandwiches to the children on paper plates. | She served sandwiches on paper plates to the children. |
| He only eats fish on Fridays. | He eats only fish on Fridays. (if that is the meaning) |
Only is worth singling out. It modifies whatever follows it, so moving it changes the meaning of the sentence completely. Place it immediately before the word it limits.
Rule 7: Keep Lists and Pairs Parallel
Items joined by and, or, or a correlative pair must share the same grammatical form.
| Wrong | Right |
|---|---|
| She likes swimming, cycling and to run. | She likes swimming, cycling and running. |
| He is not only clever but works hard too. | He is not only clever but also hard-working. |
| The job requires patience, skill and being organised. | The job requires patience, skill and organisation. |
Correlative pairs must be complete and correctly matched: not only… but also, either… or, neither… nor, both… and. Mixing them (neither… or) is an error.
Rule 8: Compare Like with Like
A comparison must hold between two comparable things, and the structure must be complete.
| Wrong | Right |
|---|---|
| The climate of London is milder than Edinburgh. | The climate of London is milder than that of Edinburgh. |
| His salary is higher than me. | His salary is higher than mine. |
| She is more taller than her sister. | She is taller than her sister. |
| He is the tallest of the two brothers. | He is the taller of the two brothers. |
Use the comparative (-er / more) for two things and the superlative (-est / most) for three or more. Never combine more with an -er form.
Family Four: Word Choice
Rule 9: Choose the Right Article
| Rule | Example |
|---|---|
| a before a consonant sound, an before a vowel sound | a university, an hour, a European, an MBA |
| the for something already identified or unique | the sun, the book I lent you |
| no article for general plurals and uncountables | I like music. Dogs are loyal. |
The sound rule catches people out. University begins with a y sound, so it takes a. Hour begins with a vowel sound because the h is silent, so it takes an.
Rule 10: Learn Verbs and Adjectives with Their Prepositions
There is no logic to these. They have to be learned as pairs, which is why they appear so often in tests.
| Wrong | Right |
|---|---|
| discuss about the plan | discuss the plan |
| married with him | married to him |
| depends of the weather | depends on the weather |
| good in mathematics | good at mathematics |
| different than mine | different from mine |
| capable of doing | capable of doing ✓ |
| prefer tea than coffee | prefer tea to coffee |
Note that discuss, enter, marry, reach and resemble take no preposition at all in standard English.
Rule 11: Count What Is Countable
| Countable | Uncountable |
|---|---|
| many, few, fewer, a number of | much, little, less, an amount of |
| fewer cars on the road | less traffic on the road |
| How many items? | How much luggage? |
Common uncountables that learners treat as plural: information, advice, furniture, luggage, equipment, news, progress, research. You cannot say informations or an advice. Use a piece of advice, two items of luggage.
Rule 12: Cut Redundancy and Double Negatives
English does not use two negatives to strengthen a point, and it dislikes saying the same thing twice.
| Wrong | Right |
|---|---|
| I don’t know nothing about it. | I don’t know anything about it. |
| Return back to the office. | Return to the office. |
| The reason is because he was late. | The reason is that he was late. |
| Repeat that again. | Repeat that. |
Words like hardly, scarcely and barely already carry a negative meaning, so I can’t hardly hear you is a double negative. It should be I can hardly hear you.
Practice Set
Find and correct the error in each sentence. Answers follow.
- Neither of the answers were correct.
- If I would have known, I would have come earlier.
- She is more better at chemistry than her brother.
- The teacher gave a advice to the students.
- Walking down the street, the shop windows looked beautiful.
- He is capable to handle the situation.
- I have met him last Tuesday.
- The committee have announced their decision.
- She likes reading, painting and to travel.
- There is less people here than yesterday.
- He said that he will call me tomorrow.
- The population of India is larger than China.
Answers
- Neither of the answers was correct. Neither is singular.
- If I had known, I would have come earlier. Third conditional — never if I would have.
- She is better at chemistry than her brother. Better is already comparative.
- The teacher gave advice to the students. Advice is uncountable; a piece of advice if you need the article.
- Walking down the street, I thought the shop windows looked beautiful. The windows were not walking.
- He is capable of handling the situation. Capable takes of + -ing.
- I met him last Tuesday. A finished time marker requires the past simple.
- The committee has announced its decision. Treat a collective noun as singular when it acts as one body.
- She likes reading, painting and travelling. Parallel structure.
- There are fewer people here than yesterday. People is countable, so fewer, and the verb becomes plural.
- He said that he would call me the next day. Sequence of tenses.
- The population of India is larger than that of China. Compare populations with populations.
Frequently Asked Questions
What is sentence correction? Sentence correction is an exercise in which you identify and fix a grammatical error in a given sentence. It appears in competitive exams, English proficiency tests and classroom grammar work, and it tests whether you can recognise standard usage rather than simply produce it.
Which errors appear most often? Subject-verb agreement is the most common by a clear margin, followed by tense errors, pronoun agreement, misplaced modifiers and faulty parallelism. If you master those five, you will handle most questions you meet.
How do I know if a sentence is already correct? Some questions have no error, and candidates lose marks by inventing one. Work through the error families deliberately rather than relying on instinct. If you check agreement, tense, pronouns, modifiers, parallelism and word choice and find nothing wrong, mark it correct with confidence.
Should I trust what sounds right? Only as a first filter. Your ear is trained by what you have heard most, which includes plenty of non-standard usage. When your ear and a rule disagree, follow the rule.
How can I improve at sentence correction quickly? Keep an error log. Every time you get one wrong, write down the sentence, the correction and the rule involved. Most people find their mistakes cluster around three or four rules, and fixing those produces a rapid jump in accuracy.
Where to Focus
Twelve rules is a lot to hold in mind at once, so do not try. Start with the three that account for most errors: subject-verb agreement, tense consistency and parallel structure. Work through practice sentences until you spot those without effort.
Then add the rest a rule at a time, keeping an error log as you go. Sentence correction rewards pattern recognition more than knowledge, and pattern recognition comes from volume. Twenty sentences a day for a fortnight will change your accuracy more than reading this article ten times.