SAT inference questions: how to complete the text logically

1. Summarise each sentence in a few words: what's the claim, what's the evidence, what's the twist?
2. Find the logic: a contrast ("however"), a finding that rules something out, or a pattern.
3. Predict the conclusion in your own words.
4. Choose the option that matches, and check it doesn't add anything the passage doesn't support.

Scientists thought a species of frog survived winter by burrowing underground. But researchers found the frogs in leaf litter on the surface, frozen solid, and they revived when the weather warmed. This suggests that ______

A) all frogs can survive being frozen. B) the frogs survive winter by tolerating freezing rather than by burrowing. C) burrowing is dangerous for frogs. D) leaf litter keeps frogs warm in winter.

The evidence contradicts burrowing and shows the frogs freeze and revive. B follows directly. A goes too far ("all frogs"); D contradicts "frozen solid".

• Too broad: "all", "always", "never" when the passage is about one case.
• True in the real world, but not shown in the passage.
• Reverses the logic, for example confusing cause and effect.
• Repeats a detail without completing the reasoning.

Explain out loud why each wrong choice is wrong; it trains you to spot overreaching answers. Mix inference questions with command of evidence questions, which use similar reasoning. See all question types.

Archaeologists found stone tools at a site dated to 12,000 years ago. Some argued the tools were left by a later group, but the tools were sealed beneath a layer of volcanic ash that has been reliably dated to 11,500 years ago. Therefore, ______

A) the tools were made by the same group that made other tools nearby. B) the tools must have been placed at the site before the ash fell. C) volcanic eruptions forced early people to leave the region. D) the later group arrived after the eruption.

The ash sealed the tools, so the tools were there before the ash, which rules out a later group. B follows. C and D might be true, but the passage doesn't show them.

• "However" or "but" near the end often means the conclusion goes against the earlier view.
• "Because" or "since" gives the evidence the conclusion rests on.
• Words of comparison ("unlike", "similarly") suggest the conclusion compares two cases.
• Qualifiers in the passage ("some", "may", "in this study") mean the conclusion should be qualified too.

When the passage uses cautious language, the right answer usually does as well. A confident, sweeping answer is a warning sign.

Inference questions are often among the slowest in Reading and Writing. If you've read the passage twice and still can't predict the conclusion, eliminate the clearly extreme choices, pick the best of what's left, mark it for review and move on. Come back with fresh eyes if time allows; the answer is often clearer the second time. You'll find similar reasoning in cross-text and central idea questions.