Modal Verbs of Probability in Technical Communication
5 exercises — must for logical conclusions, may/might for possibility, could for remote possibility, and can't for near impossibility.
0 / 15 completed
1 / 15
The CPU has been at 100% for 20 minutes and no processes are responding. Which modal is most appropriate? "There _____ an infinite loop in the worker thread."
"Must be" expresses a logical deduction from strong evidence. When the evidence is compelling and near-certain, "must" is the correct choice. Compare: "might be" (uncertain), "could be" (possible but not deduced), "can't be" (near impossibility).
2 / 15
A deploy succeeded but some users are reporting 404s. Which sentence best expresses uncertainty? "The routing configuration _____ updated correctly during the release."
"Might not have been" expresses past possibility/uncertainty. "Must not have been" and "can't have been" are both near-certain deductions (negative), which would be too strong when we are simply unsure. "Should not have been" expresses obligation/expectation, not probability.
3 / 15
You see memory usage increasing steadily. Which statement uses the modal correctly?
"Might be" correctly signals an unconfirmed hypothesis during debugging. Using "might" then recommending investigation is a natural and precise debugging communication pattern.
4 / 15
The error log shows a null pointer exception in a function that was refactored an hour ago. "The recent refactor _____ introduced this bug."
"Could have" introduces a past possibility without asserting it as certain. It is appropriate when you have a plausible hypothesis but not conclusive proof. "Must have" would assert near-certainty; "can't have" would deny it.
5 / 15
The feature flag was disabled company-wide. "The new checkout flow _____ the cause — it is disabled for all users."
"Can't be" expresses a logical impossibility based on evidence. Since the feature is disabled, it logically cannot be the cause. This is the negative deduction counterpart to "must be" (positive deduction).
6 / 15
Alex: 'I'm seeing a spike in latency on the API calls. It might be related to the database migration we did last night.'
Which modal verb best expresses Alex's assessment of the situation?
'Likely' indicates a reasonable probability based on correlation, which is appropriate in this technical context. The other options assume absolute certainty ('certain') or suggest an alternative explanation without sufficient evidence ('definite'). The phrasing highlights that the migration *might* be involved.
7 / 15
Alex: 'I'm seeing a spike in latency on the API calls. It might be related to the database migration we did last night.'
Which modal verb best expresses Alex's assessment of the situation?
'Likely' indicates a reasonable probability based on correlation, which is appropriate in this technical context. The other options assume absolute certainty ('certain') or suggest an alternative explanation without sufficient evidence ('definite'). The phrasing highlights that the migration *might* be involved.
8 / 15
Sarah: 'The build failed unexpectedly. I suspect a problem with the CI/CD pipeline.' Which modal verb best expresses Sarah's assessment?
'Should' indicates a reasonable probability based on evidence. 'Must' implies certainty which isn't appropriate here; 'will' suggests a prediction, not an assessment of likelihood. 'Could' is too weak to convey Sarah's suspicion about the pipeline.
9 / 15
During a code review, you read: 'The API response might be returning an empty list when no data is available.' Which modal verb best fits this context?
'May' is the most accurate choice here to express possibility. 'Will' implies a definite future event; 'must' suggests certainty and doesn't align with the uncertain nature of the API response. 'Can' indicates ability, not probability.
10 / 15
The automated tests consistently fail after a recent code merge. Mark: 'There _____ be an issue with the integration between the microservices.' Which modal verb is most appropriate?
'Are' is used to express a possibility or probability when referring to plural subjects. 'Is' would only work if the subject were singular. 'Could be' and 'should be' imply stronger assumptions than are warranted by the initial failure; Mark is simply suggesting a potential cause.
11 / 15
After investigating a performance bottleneck, Liam says: 'The increased database load _____ be contributing to the slowdown.' Which modal verb best expresses Liam's assessment?
'Are' is used to express a probability or possibility when referring to plural subjects. 'Is' would only work if the subject were singular. 'Could be' and 'will be' suggest prediction or strong certainty which isn't justified by the initial observation.
12 / 15
In a PR description for a new feature update, Maria writes: 'The updated authentication service probably won't impact existing user flows.' Which modal verb is most appropriate to convey this cautious assessment?
A) The authentication service will impact…
B) The authentication service should impact…
C) The authentication service might not impact…
D) The authentication service has to impact…
Maria is expressing a probability, acknowledging that it's possible the service *could* have an effect. 'Might not' accurately reflects this uncertainty. Options A and B imply certainty where none exists; D implies an obligation or requirement which isn't stated.
13 / 15
A senior developer, Sarah, is writing a comment about a potential issue with the deployment process. She writes: 'There might be some residual data causing intermittent errors.' Which modal verb best expresses her cautious assessment?
'Likely' accurately reflects Sarah's assessment that there's a high probability of leftover data causing problems. The other options suggest certainty or lack of concern which are inappropriate for a potential issue in a production environment. The key here is acknowledging uncertainty about the effect.
14 / 15
A junior developer, Alex, is drafting a Slack message to his team about a newly discovered bug in a critical module. He writes: 'The error log shows a null pointer exception... it probably needs investigation.' Which modal verb best fits this context?
'Probably' is the most appropriate modal verb here because Alex is expressing a reasonable probability of a problem without claiming absolute certainty. The null pointer exception represents a potential risk that warrants investigation. The other options imply more confidence than he can reasonably have at this stage.
15 / 15
During a code review, you're examining a pull request and the author writes: 'The recent refactor probably introduced this bug.' Which modal verb best reflects the author's assessment?
'Likely' is the most suitable choice. The author acknowledges a strong probability that the refactor caused the bug, recognizing potential correlation without definitive proof. 'Certain' would be too assertive, and the other options suggest unnecessary actions or assumptions.
What will I practise in "Modal Verbs of Probability in Technical Communication — Grammar Exercise"?
Practice must, may, might, could, and can't to express degrees of certainty and probability in technical communication and debugging.
How many exercises are in this module?
This module has 15 multiple-choice exercises, each with instant feedback and a full explanation of the correct answer.
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Every exercise is written by the CoderSlingo team, drawing on real workplace English used in IT roles, then reviewed for accuracy and clarity.