IMAT Reading Skills and General Knowledge · Reading Comprehension
Negative Stems, Causes and Half-Right Options
Some stems ask for the one option the text does not support, and some ask why something happens; both reward checking every part of every option.
Why this matters
The 2024 paper asked which statement CANNOT be inferred, and the 2025 paper which statement is NOT correct. The 2026 paper asked twice for the reason or main cause the author gives, with options that were right in one half and wrong in the other.
Concept 1 of 3: Negative stems: CANNOT be inferred, NOT correct, EXCEPT
A negative stem turns the task upside down: four options are supported, and the answer is the odd one out. Under time pressure, students forget the NOT halfway through and choose the first statement they find in the text. Labelling every option stops that.
Definition
- Negative stems: 'Which CANNOT be inferred', 'Which is NOT correct', 'All of the following are stated EXCEPT', 'Which is NOT consistent with the text'.
- Method: label each option Y (the text supports it) or N (the text contradicts it or does not support it). Exactly one should be N, and that is the answer.
- If you find two Ns, one of your Ys is wrong, or one of your Ns: reread both candidates against their lines.
- 'CANNOT be inferred' covers options the text contradicts and options it simply does not support.
- Before reading the options, say the task to yourself in plain words: 'find the one the text does not back up'.
Worked example
Before the 1840s, surgery was performed on patients who were fully awake, so surgeons valued speed above all, and few operations went deeper than the limbs. In 1846, at a hospital in Boston, the dentist William Morton gave a patient ether vapour to breathe before a tumour was removed from his neck, and the patient later said he had felt no pain. News of the demonstration reached Europe within months. Chloroform, introduced a year later, was easier to use but proved more dangerous to the heart. Anaesthesia allowed longer and more careful operations, although without antiseptic methods many patients still died of infection afterwards.
Which of the following CANNOT be inferred from the text?
(A) Before ether was used, operations had to be fast.
(B) The 1846 demonstration was soon known outside America.
(C) Chloroform came into use in 1847.
(D) After 1846, deaths after surgery fell almost to zero.
(E) Anaesthesia made longer operations possible.
Practice this conceptself-check · 3 quick reps
Forgetting the NOT halfway through
In a negative question the four options you can find in the text are the wrong answers. A student who reads an option, finds it in the passage and chooses it has answered the opposite question. Write Y or N next to every option and choose the single N.
Concept 2 of 3: Cause and reason questions: finding the author's own explanation
A 'why' question asks for the reason the text gives, not a reason that merely sounds sensible. Texts mark causes with small words: because, since, so, led to, due to. Wrong options reverse cause and effect, give the cause of a different event in the passage, or turn one of several factors into the only one.
Definition
- Find the signal words: because, since, as, so, therefore, thus, led to, resulted in, due to, owing to, the reason is, this is why.
- Identify the effect the question asks about, then find the cause the text attaches to that effect.
- Wrong options: reverse cause and effect; give the cause of a different effect in the passage; give a second effect of the same cause; turn one of several factors into the only one; offer a cause the reader might believe but the text never states.
- 'Primarily', 'mainly' and 'above all' in a stem ask for the cause the text ranks first. Look for ranking words in the text: above all, mainly, chiefly, the main reason.
Worked example
The dodo, a large flightless pigeon, lived only on the island of Mauritius. Having evolved without land predators, it nested on the ground and showed little fear of people. Dutch sailors began to visit the island in 1598 and hunted the birds for food, but historians now think that hunting alone did not finish them off. The sailors also brought rats, pigs and monkeys, which ate the dodo's eggs and chicks, and forests were cleared for settlement. The last widely accepted sighting dates from 1662. Because the dodo laid a single egg at a time, its numbers could not recover quickly from these losses.
According to the text, why were the dodo's losses hard to make up?
(A) Because sailors hunted the birds for food.
(B) Because each bird laid only one egg at a time.
(C) Because the dodo could not fly.
(D) Because the dodo lived only on Mauritius.
(E) Because forests were cleared for settlement.
Practice this conceptself-check · 3 quick reps
Reversing cause and effect
If a text says that a shortage of nurses led to longer waiting lists, an option saying that long waiting lists caused the shortage reverses it. Find which event the text puts first in the chain, and check that the option keeps the same order.
Concept 3 of 3: Options that are only half right
Long options are often two claims joined by 'and', 'because', 'where' or 'both'. If one half is wrong, the whole option is wrong. A favourite design puts the correct idea at the start of several options and changes only the ending, so the student who stops reading halfway picks a wrong one.
Definition
- Split a long option at and, because, so, where, which, both ... and, as well as.
- Check each part against the text. One unsupported part makes the whole option wrong.
- When several options share the same opening, the difference is in the endings: compare only the endings.
- An option that adds a second cause ('both X and Y') is wrong if the text names only X, or says Y does something else.
- An extra detail the text never mentions (a place, a group, a date) is enough to rule an option out.
Worked example
In 1816 the French physician René Laennec was examining a young woman with heart trouble. Placing an ear directly on the patient's chest was the usual method, but he found it improper in this case and, in any event, of little use because of her build. He rolled a sheet of paper into a tube, put one end to her chest and the other to his ear, and heard the heartbeat more clearly than ever before. He went on to build wooden tubes and spent three years linking the sounds he heard to the diseases he later found at autopsy. His book of 1819 made listening to the chest a standard part of examination.
According to the text, Laennec first used a paper tube because:
(A) direct listening seemed improper for this patient and would have helped little.
(B) direct listening seemed improper and he had already built wooden tubes.
(C) he wanted to link heart sounds with autopsy findings and to write a book.
(D) direct listening was the usual method and was forbidden by law.
(E) the patient asked him not to touch her and her heartbeat was very loud.
Practice this conceptself-check · 3 quick reps
One correct half does not make an option correct
An option that starts with the text's exact idea and then adds something the text never says is wrong. Read every option to its last word; the error is often in the final few words.
Summary — formulas & gotchas at a glance
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Watch out for (3)
- Forgetting the NOT halfway through→ Negative stems: CANNOT be inferred, NOT correct, EXCEPT
- Reversing cause and effect→ Cause and reason questions: finding the author's own explanation
- One correct half does not make an option correct→ Options that are only half right
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