5 exercises — must/should/could/might/may for RFC-style requirements, API docs, code review comments, and architecture proposals.
0 / 20 completed
1 / 20
An API specification states a security requirement. Choose the correct modal: "All API requests _____ include a valid Bearer token in the Authorization header."
"Must" expresses an absolute mandatory requirement with no exceptions permitted. In RFC 2119 terminology (used by IETF standards and most API specs), MUST means the requirement is unconditional. "Should" allows exceptions in specific circumstances; "might" and "could" are far too weak for a security requirement. When writing API specs, use MUST/MUST NOT for non-negotiable security constraints.
2 / 20
A code review comment reads: "This function _____ validate input before passing it to the database layer." What modal best expresses a strong recommendation (not a hard rule)?
"Should" expresses a strong recommendation while acknowledging that specific circumstances might justify an exception. In code reviews, "should" signals a real concern without claiming the current code is definitively wrong. "Must" would be appropriate if this were a security-critical requirement with no exceptions. RFC 2119: "SHOULD means there may exist valid reasons in particular circumstances to ignore this requirement."
3 / 20
An incident retrospective identifies a potential contributing factor. Which sentence uses the correct modal?
"Might be caused by" expresses a hypothesis with low certainty — appropriate when a root cause has not been confirmed. Post-mortems use this hedging modal during the investigation phase. "Must" implies near-certainty from logical deduction. "Should" implies expectation, which is semantically wrong here. "Will" incorrectly implies future tense.
4 / 20
A deployment guide recommends a caching duration. Choose the best sentence:
"Should" establishes the recommended default (strong advice, implementable without exceptions for most cases). "May" then permits a specific extension under a defined condition — this is RFC 2119-compliant writing. Option A is too rigid for a caching recommendation. Option B is too tentative and informal. Option D is over-hedged to the point of uselessness.
5 / 20
An infrastructure team is discussing scaling options. Choose the sentence that uses modals most precisely for a technical proposal:
Three modals used precisely: "could" (capability — horizontal scaling is able to handle the load), "should" (strong recommendation — evaluating connection limits is important), "might" (low certainty — vertical scaling is possibly sufficient but not certain). This layered modal usage signals engineering rigour. Options A and D are too vague or overconfident; B uses "must" and "will" inappropriately for a proposal that should acknowledge uncertainty.
6 / 20
DevOps is requesting a review of the new deployment script. He comments: 'The container image must be tagged with the release version before pushing to Docker Hub.' What modal verb best expresses this requirement?
'Must' denotes a strict obligation or necessity in technical contexts like deployment procedures. Using 'should' would suggest a recommendation, while 'can' and 'may' indicate possibility rather than a required action. This aligns with the need to ensure consistent tagging for traceability.
7 / 20
Sarah, a junior developer, writes in a Slack channel: 'I'm going to log this error. I need to investigate the root cause and fix it ASAP.' Which modal verb best reflects her urgency and responsibility?
'Need to' expresses a strong obligation and requirement when dealing with errors and bugs. 'Might,' 'could,' and 'will' all suggest lower levels of certainty or probability, which aren't appropriate when emphasizing the immediate need for action in this scenario. It highlights her responsibility to resolve the issue.
8 / 20
You're drafting a Pull Request description for a change that improves database query performance. You want to state that the new index should be created automatically on every table update. Which modal verb is most appropriate?
'Must' indicates a firm requirement or necessity – in this case, the index creation should be enforced as part of the database schema update process. 'Will' suggests prediction, while 'may' and 'could' offer less certainty about the automated execution. Enforcing it is crucial for maintaining data integrity.
9 / 20
During a daily standup, Mark reports on his progress: 'I've finished implementing the authentication flow. I can test it thoroughly before submitting the code.' What modal verb best describes the current state of his work?
'Can' indicates ability and possibility – Mark is stating that he possesses the capacity to test the authentication flow. 'Must' would imply a requirement, while 'should' suggests recommendation and 'will' predicts future action. The ability to test is key at this stage.
10 / 20
The documentation for the new API endpoint states: 'Clients are required to provide a valid JWT token in the header to access protected resources.' What modal verb best conveys this specification?
'Must' is the most precise modal verb for expressing requirements within API specifications. It signifies a mandatory condition that clients *have* to fulfill for the endpoint to function correctly. 'May,' 'should,' and 'could' would introduce ambiguity or suggestion, which isn't appropriate for defining API behavior.
11 / 20
DevOps is requesting a review of the new deployment script. He comments: 'The container image must be tagged with the release version before pushing to Docker Hub.' What modal verb best expresses this requirement?
'Must' denotes a strict obligation or necessity in technical contexts like deployment procedures. Using 'should' would suggest a recommendation, while 'can' and 'may' indicate possibility rather than a required action. This aligns with the need to ensure consistent tagging for traceability.
12 / 20
Sarah, a junior developer, writes in a Slack channel: 'I'm going to log this error. I need to investigate the root cause and fix it ASAP.' Which modal verb best reflects her urgency and responsibility?
'Need to' expresses a strong obligation and requirement when dealing with errors and bugs. 'Might,' 'could,' and 'will' all suggest lower levels of certainty or probability, which aren't appropriate when emphasizing the immediate need for action in this scenario. It highlights her responsibility to resolve the issue.
13 / 20
You're drafting a Pull Request description for a change that improves database query performance. You want to state that the new index should be created automatically on every table update. Which modal verb is most appropriate?
'Must' indicates a firm requirement or necessity – in this case, the index creation should be enforced as part of the database schema update process. 'Will' suggests prediction, while 'may' and 'could' offer less certainty about the automated execution. Enforcing it is crucial for maintaining data integrity.
14 / 20
During a daily standup, Mark reports on his progress: 'I've finished implementing the authentication flow. I can test it thoroughly before submitting the code.' What modal verb best describes the current state of his work?
'Can' indicates ability and possibility – Mark is stating that he possesses the capacity to test the authentication flow. 'Must' would imply a requirement, while 'should' suggests recommendation and 'will' predicts future action. The ability to test is key at this stage.
15 / 20
The documentation for the new API endpoint states: 'Clients are required to provide a valid JWT token in the header to access protected resources.' What modal verb best conveys this specification?
'Must' is the most precise modal verb for expressing requirements within API specifications. It signifies a mandatory condition that clients *have* to fulfill for the endpoint to function correctly. 'May,' 'should,' and 'could' would introduce ambiguity or suggestion, which isn't appropriate for defining API behavior.
16 / 20
DevOps is requesting a review of the new deployment script. He comments: 'The container image must be tagged with the release version before pushing to Docker Hub.' What modal verb best expresses this requirement?
'Must' denotes a strict obligation or necessity in technical contexts like deployment procedures. Using 'should' would suggest a recommendation, while 'can' and 'may' indicate possibility rather than a required action. This aligns with the need to ensure consistent tagging for traceability.
17 / 20
Sarah, a junior developer, writes in a Slack channel: 'I'm going to log this error. I need to investigate the root cause and fix it ASAP.' Which modal verb best reflects her urgency and responsibility?
'Need to' expresses a strong obligation and requirement when dealing with errors and bugs. 'Might,' 'could,' and 'will' all suggest lower levels of certainty or probability, which aren't appropriate when emphasizing the immediate need for action in this scenario. It highlights her responsibility to resolve the issue.
18 / 20
You're drafting a Pull Request description for a change that improves database query performance. You want to state that the new index should be created automatically on every table update. Which modal verb is most appropriate?
'Must' indicates a firm requirement or necessity – in this case, the index creation should be enforced as part of the database schema update process. 'Will' suggests prediction, while 'may' and 'could' offer less certainty about the automated execution. Enforcing it is crucial for maintaining data integrity.
19 / 20
During a daily standup, Mark reports on his progress: 'I've finished implementing the authentication flow. I can test it thoroughly before submitting the code.' What modal verb best describes the current state of his work?
'Can' indicates ability and possibility – Mark is stating that he possesses the capacity to test the authentication flow. 'Must' would imply a requirement, while 'should' suggests recommendation and 'will' predicts future action. The ability to test is key at this stage.
20 / 20
The documentation for the new API endpoint states: 'Clients are required to provide a valid JWT token in the header to access protected resources.' What modal verb best conveys this specification?
'Must' is the most precise modal verb for expressing requirements within API specifications. It signifies a mandatory condition that clients *have* to fulfill for the endpoint to function correctly. 'May,' 'should,' and 'could' would introduce ambiguity or suggestion, which isn't appropriate for defining API behavior.
What will I practise in "Modal Verbs in Technical English — Grammar Exercise"?
Practice modal verbs for writing technical recommendations, system requirements, API documentation, and architecture proposals.
How many exercises are in this module?
This module has 20 multiple-choice exercises, each with instant feedback and a full explanation of the correct answer.
Is this exercise free to use?
Yes. Every exercise on CoderSlingo, including this one, is free to use with no account, sign-up, or paywall.
Do I need to create an account to do these exercises?
No account is required. Just click an option to answer — your score for this session is tracked automatically in the progress bar above.
What happens if I choose the wrong answer?
You'll immediately see which answer was correct, plus a full explanation covering the grammar rule and reasoning behind it — mistakes are where most of the learning happens.
Can I retry the exercises if I want a higher score?
Yes — use the "Try again" button on the results screen to reset and go through all the questions again.
Is my progress saved if I close the page?
No. Progress is tracked only for your current visit; reloading or leaving the page resets the counter. This keeps the exercise simple and account-free.
Where can I find more Grammar exercises?
Browse the full Grammar hub for related drills, or check the "Next up" link below to continue with a connected topic.
How is this different from reading an article on the same topic?
Articles explain grammar rules in prose; this exercise tests and reinforces those rules through active recall with immediate feedback — the two work best together.
Who writes these exercises?
Every exercise is written by the CoderSlingo team, drawing on real workplace English used in IT roles, then reviewed for accuracy and clarity.