Passage-based critical reasoning asks you to evaluate an argument rather than rely on outside knowledge. Read the passage as a small logical system: identify what evidence is stated, what conclusion is drawn, and whether the evidence truly supports it.

1. Parts of an argument

• Premise: a fact, observation, or claim offered as support.
• Conclusion: the main claim the author wants you to accept.
• Assumption: an unstated idea that must be true for the argument to work.
• Inference: a conclusion that follows directly from the stated information.
• Evidence: information that can strengthen, weaken, or explain the argument.

2. Common question types

• Main conclusion: find the claim supported by the other statements.
• Assumption: identify the necessary bridge between evidence and conclusion.
• Strengthen: choose evidence that makes the conclusion more likely.
• Weaken: choose evidence that makes the conclusion less likely.
• Inference: choose only what must be true, not what could be true.
• Flaw: identify an unsupported leap, comparison, or cause-and-effect error.

3. A reliable solving method

1. Read the question stem first, because the task determines what evidence matters.
2. Mark the conclusion and separate it from the premises.
3. State the argument in a short form: premise therefore conclusion.
4. Test each option only against the task asked; a relevant fact may still fail to strengthen or weaken.
5. Reject answers that require new assumptions or go beyond the passage.

4. How to test assumptions

Use the negation test. Negate a possible assumption and ask whether the argument falls apart. If the conclusion can no longer follow, that statement was necessary. For strengthening and weakening questions, ask whether the option closes or widens the gap between the stated evidence and the conclusion.

Common mistakes

• Choosing an answer because it is generally true, rather than because the passage supports it.
• Confusing a premise with the author's conclusion.
• Treating a statement that merely repeats a premise as a strong argument.
• Assuming correlation proves causation.
• Selecting an inference that is possible but not logically required.

Quick revision summary

• Use only the passage information unless the question explicitly says otherwise.
• Find the conclusion before evaluating the options.
• Strengthen closes a logical gap; weaken opens one.
• An inference must be certain from the stated facts.