Error Spotting
🔒 Log in to trackVerb forms, question tags, conditionals and structure
🔒 Log in to trackErrors that are not agreement, tense, article or preposition, but live in the shape of the sentence: which verb form follows another verb (gerund or infinitive), the tag at the end of a statement, the two halves of a conditional, lists that must keep one shape, adjectives where adverbs are needed, and modal verbs that never take 'to' or 'able to' alongside.
Detailed notes
Verb + verb: gerund or infinitive
Some verbs are followed by the -ing form (gerund), some by to + verb (infinitive), and a few by either with a meaning change.
- Always + -ing: enjoy, avoid, deny, suggest, mind, finish, keep, practise, look forward to, be used to, insist on, interested in, capable of. Correct: He denied taking the file. Incorrect: He denied to take the file.
- Always + to + verb: want, hope, decide, agree, refuse, promise, manage, afford, learn. Correct: They decided to leave early.
- look forward to + -ing is the most planted trap: Correct: I look forward to meeting you. Incorrect: …to meet you. (Here 'to' is a preposition, not part of the infinitive.)
- Preposition + -ing always: interested in painting, good at singing, afraid of falling.
Question tags: flip the sign, match the pronoun
A tag repeats the helping verb of the statement, flips it negative/positive, and ends with a pronoun that matches the subject.
- Positive → negative tag: They have submitted their projects, haven't they? (never 'isn't it?')
- Negative → positive tag: He doesn't smoke, does he?
- Hidden negatives — never, rarely, seldom, hardly, scarcely, little — make the statement negative: Suresh rarely misses his walk, does he?
- I am → aren't I?; Let's → shall we?; an imperative → will you?
Conditionals: two halves, one pattern
| Type | If-clause | Main clause | Example |
|---|---|---|---|
| Real future | simple present | will + verb | If she works hard, she will qualify. |
| Unreal present | simple past | would + verb | If I were rich, I would travel. |
| Unreal past | had + participle | would have + participle | If I had known, I would have left earlier. |
| Planted errors: will inside the if-clause; would have inside the if-clause of the unreal past. |
Parallelism: keep the list in one shape
Items joined by and / but / or / not only…but also must share their form.
- Correct: The policy aims at reducing paperwork, improving transparency, and speeding up file movement.
- Incorrect: …and to speed up file movement. (One -ing among to-forms breaks the line.)
- Correct: She enjoys cooking and gardening. Incorrect: She enjoys cooking and to garden.
Adjective or adverb?
- Adjectives describe nouns; adverbs describe actions.
- After an action verb → adverb: The engine runs smoothly. Incorrect: runs smooth.
- After sense/linking verbs (be, seem, taste, smell, feel, look when describing the subject) → adjective: The mangoes taste delicious. Incorrect: taste deliciously (the mangoes are delicious, they do not taste in a delicious manner).
Modals: bare and unbending
After can, could, may, might, must, shall, should, will, would the base verb follows — no to, no able to:
- Correct: You must submit the form by Friday. Incorrect: must to submit.
- Correct: She could not explain the gap. Incorrect: could not able to explain — 'could' already says ability; 'able to' says it again and breaks the grammar. Ability: can swim; necessity: must go; possibility: may come.
Quick revision
- enjoy / avoid / deny / look forward to + -ing; want / decide / agree + to + verb.
- Preposition (in, of, at, to as preposition) + -ing.
- Tag = helping verb flipped + matching pronoun; rarely/never/hardly → positive tag.
- If-clause: future → present; unreal past → had + participle (never would have).
- Lists stay parallel: one shape for every item.
- Runs smoothly (action), tastes delicious (linking); must submit, could explain — never 'to' or 'able to' after a modal.
Types of questions asked
Every way this subtopic shows up in exams — how to recognise it, the formula or logic to use, and a solved example.
Type 1: Gerund vs infinitive after a verb or prepositionvery common2 practice Q
The suspect verb follows another verb or a preposition, and the options offer -ing vs to + verb forms.
- Identify the verb or preposition before the blank.
- -ing group: enjoy, avoid, deny, suggest, look forward to, interested in, capable of.
- to-group: want, decide, agree, refuse, manage.
- After a preposition (including the 'to' of look forward to), always -ing.
Why it works: the two groups are fixed by habit; 'look forward to see' is the single most common Indian-English slip.
Example: "The children are looking forward to (1) ______ the circus next week." see / seeing / be seeing / saw
In look forward to, 'to' is a preposition → -ing follows: seeing. 'Look forward to see' is the planted error.
Type 2: Question tag sign and pronounvery common2 practice Q
The sentence ends with a short tag after a comma, and the options are different tags (isn't it?, haven't they?, does he?).
- Find the helping verb of the statement.
- Flip its sign; the statement's subject becomes a pronoun in the tag.
- Hidden negatives (never, rarely, hardly) → positive tag.
Why it works: 'isn't it?' is used for every statement in spoken Indian English, so it is the default wrong option.
Example: "Suresh rarely misses his morning walk, (1) ______?" doesn't he / does he / isn't it / hasn't he
Rarely makes the statement negative → positive tag with the right helper: does he. 'Doesn't he' fails to flip; 'isn't it' matches no subject.
Type 3: Conditional half brokencommon2 practice Q
An if-sentence shows the wrong pair: will inside the if-clause, or would have inside the if-clause of an unreal past.
- Read both halves of the conditional.
- Real future: if + present, will + verb in the main clause.
- Unreal past: if + had + participle, would have + participle — never 'would have' inside the if-clause.
Why it works: 'If I would have known' is common in speech; standard English keeps would out of the if-clause.
Example: "(1) ______ about the traffic, I would have left much earlier." If I would have known / If I had known / If I knew / If I have known
Unreal past → if + had known; the main clause keeps 'would have left'. 'Would have known' belongs only in the main clause.
Type 4: Broken parallelism in a listcommon2 practice Q
Three items are joined by and/but, and one item changes shape (two -ing forms and one to-form, or a noun among gerunds).
- List the joined items in a column.
- Check every item's shape against the first.
- Rewrite the odd item to copy the first — the odd item is the error.
Why it works: the eye reads lists as a single unit, so a shape change hides until you check item by item.
Example: "My grandmother enjoys cooking, (1) ______, and long walks in the park." to garden / gardening / garden / for gardening
The list runs on gerunds after enjoys: cooking, gardening, (taking) walks. 'To garden' breaks the shape.
Type 5: Adjective where an adverb belongs (or the reverse)occasional2 practice Q
A word describing an action is in adjective form (runs smooth), or a word after a linking verb is in adverb form (tastes deliciously).
- Ask what the word describes: an action (how it runs?) or the subject's state (how it tastes?).
- Action → adverb (-ly); subject state after a linking verb → adjective.
- The classic pair: runs smoothly / tastes delicious.
Why it works: both errors sound natural in casual speech; the verb's type decides which is standard.
Example: "The new engine runs very (1) ______ and hardly makes any noise." smooth / smoothly / smoothness / smoother
'Runs' is an action verb → describe it with an adverb: smoothly. 'Runs smooth' leaves the action undescribed.
Type 6: Modal + to/able-to errorcommon2 practice Q
A modal (can, could, must, should) is followed by 'to + verb' or by 'able to', doubling or breaking the structure.
- Spot the modal and the verb after it.
- Modals take the bare base verb: must submit, could explain, can swim.
- 'Could able to' doubles ability — delete 'able to'; 'must to' doubles the marker — delete 'to'.
Why it works: 'can able to' is a direct translation habit, and it appears in papers exactly as often.
Example: "The candidate could not (1) ______ the gap in his employment." able to explain / explain / explaining / to explain
After could, the bare base verb: could not explain. 'Able to explain' duplicates the ability already inside 'could'.
Shortcut tricks
⚡ Question-tag flip
Hear the sentence end: a statement + tag must flip sign — positive statement → negative tag, negative word (never, rarely, hardly) → positive tag.
⚡ Unreal-past conditional
After 'if' about the unreal past, English wants had + participle — 'would have' in the if-clause is the planted error.
⚡ Parallel lists
A list is parallel: whatever shape the first item takes (-ing, to + verb, bare noun), the rest must copy it.
Where students lose marks
Using 'could able to' or 'can able to' — can/could already carry ability; only the base verb follows.
Writing 'He denied to take the file' — deny, enjoy, avoid, suggest take the -ing form, not the infinitive.
Tagging a positive statement with a positive tag ('They have come, isn't it?') — the sign must flip and the pronoun must match the subject.
Practice sets — 12 questions
Sets of 10, mixed across the question types above. Each answer comes with a step-by-step explanation.
Topic test · 12 questions
Suggested time 8 min · wrong answers go to your mistake notebook automatically.