A developer writes in a postmortem: "The memory usage _____ caused the OOM kill — we need to run a heap profiler to confirm." Which modal best expresses a strong but unconfirmed hypothesis?
Must have is correct. In epistemic modality, must have expresses a logical deduction — the speaker is highly confident based on available evidence but has not confirmed it. "The memory usage must have caused the OOM kill" communicates "this is the most likely explanation given what we observe." Will have is a prediction about completed action (not used for deductions). Should have implies it was expected to happen. Would have signals a conditional or hypothetical.
2 / 10
An architect writes in a design doc: "Switching to event-driven architecture _____ reduce the coupling between services — but we should prototype it first." Which modal correctly signals a confident recommendation with residual uncertainty?
Should is correct. Should expresses deontic recommendation and epistemic expectation simultaneously — "we believe this will work, and we recommend it." It is the standard modal for confident technical recommendations that are not absolute guarantees. Might is too tentative for a recommendation. Must is too strong — it implies logical certainty or obligation. Can expresses capability, not likelihood or recommendation.
3 / 10
A code reviewer comments: "This approach _____ work in most cases, but edge cases with null values will cause a crash." Which modal is most accurate?
Could is correct. Could expresses possibility — "there are circumstances where this works." The sentence acknowledges partial validity before identifying the failure case. Must implies logical certainty, which conflicts with "but". Shall is a strong future/obligation marker, not suitable here. Would implies a conditional ("if X, then it would work") but the sentence is not structured as a conditional.
4 / 10
A tech lead writes in a risk assessment: "The cache invalidation bug _____ affect users in the EU region — we're still investigating the scope." Which modal signals genuine uncertainty about whether it will happen?
May is correct. May expresses open possibility — the speaker does not know whether the event will occur. It is distinct from might (more tentative) and could (more hypothetical). In formal technical risk communication, may is the standard choice when the outcome is genuinely uncertain. Must implies certainty. Will states a prediction as fact. Should implies expectation, not uncertainty.
5 / 10
In a sprint planning meeting, an engineer says: "The migration _____ take about three days, assuming no blockers." Which modal is most appropriate for a professional estimate?
Should is correct in this context. Should signals an expectation based on current knowledge while acknowledging that conditions could change — exactly right for professional estimates. The phrase "assuming no blockers" reinforces this conditionality. Must states obligation or certainty — too strong for an estimate. Will commits too firmly without acknowledging uncertainty. Might is too tentative — it suggests low confidence in an estimate the engineer actually has a reasonable basis for.
6 / 10
An SRE writes in an incident report: "The latency spike _____ been caused by the deployment at 14:22 UTC — the timing is consistent." Which auxiliary completes the past epistemic deduction correctly?
Must have is correct. This is a past epistemic deduction — the speaker is reasoning from evidence (timing consistency) to a confident conclusion about a past event. Must have + past participle is the standard structure for "I am highly confident this happened, based on the evidence." Could have would express possibility, not confident deduction. Should and might are present-tense forms and do not work with the perfect aspect needed here.
7 / 10
A product manager writes: "The new feature _____ improve conversion rates based on A/B test data — we'll confirm after the full rollout." Which modal most accurately signals evidence-based confidence with residual uncertainty?
Should is correct. The sentence expresses expectation grounded in data, not certainty — which is exactly the epistemic weight of should. "Based on A/B test data" signals evidence, and "we'll confirm" acknowledges that it is not yet proven. Must is too strong — it would imply certainty. Shall is archaic or legalistic in this context. Need to expresses necessity, not probability.
8 / 10
Which sentence uses epistemic modality incorrectly in a technical context?
Option C is incorrect. Must expresses epistemic certainty or logical deduction — using it with "I'm not sure yet" creates a direct contradiction. If there is uncertainty, the correct modals are might, could, or may. Options A and D use possibility modals correctly. Option B uses must have correctly as a confident past deduction supported by evidence ("the log confirms it").
9 / 10
A senior engineer reviewing a PR comments: "This _____ cause issues in production — I'd test it against a dataset larger than 10,000 records before merging." Which modal signals a genuine concern without certainty?
Could is correct. The reviewer is not certain the code will fail, but they identify a plausible failure mode — which is exactly the epistemic weight of could (possibility, not certainty). The suggestion to test confirms that the reviewer is not certain. Will states the failure as a certainty, which is too strong for a code review concern. Should implies expectation. Must implies logical necessity or obligation, neither of which fits a possibility concern.
10 / 10
An architect writes in an RFC: "Adopting this pattern _____ introduce additional operational complexity, which teams _____ need to account for in their capacity planning." Which pair of modals is most appropriate?
Might / will is the best pair. The first clause introduces a possible risk ("might introduce") — appropriate epistemic hedging in an RFC where the pattern has not yet been adopted. The second clause is a conditional consequence: if complexity increases, teams will need to account for it — a logical consequence stated with appropriate certainty. Will / must makes both clauses too certain. Should / need to uses expectation where possibility is intended. Could / would creates a detached, overly hypothetical tone unsuitable for a planning document.
What will I practise in "Epistemic Modality in Technical English — Grammar Exercise"?
Practice expressing degrees of certainty using must, should, might, could, will, would in technical predictions, recommendations, and specifications.
How many exercises are in this module?
This module has 10 multiple-choice exercises, each with instant feedback and a full explanation of the correct answer.
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