5 exercises — practise substituting 'one'/'ones' for previously mentioned nouns, and knowing when not to.
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1 / 26
Which sentence correctly uses "one" to avoid repeating a previously mentioned countable noun?
"One" substitutes for a previously mentioned singular countable noun ("endpoint") when a modifier ("new") is added, avoiding awkward repetition. Option B is correct: "created a new one" = "created a new endpoint". Option A repeats "endpoint" verbatim, which is grammatical but more repetitive than necessary in fluent writing. Option C incorrectly uses "it", which substitutes for the exact same specific referent, not a new, different instance of the same category — "it" would wrongly imply the team recreated the very same old endpoint. Option D omits the noun/pronoun entirely after the adjective "new", which is ungrammatical — English requires either the noun or a substitute pronoun after a standalone modifying adjective in this position.
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Which sentence correctly uses "ones" (plural) to avoid repeating a plural countable noun?
"Ones" is the plural form of the substitute pronoun "one", used here to stand in for "test cases" after the modifier "more reliable". Option B is correct: "more reliable ones" = "more reliable test cases". Option A repeats the full noun phrase, which is grammatical but wordier. Option C incorrectly uses singular "one" for a plural referent — number agreement is required between the substitute pronoun and what it replaces. Option D incorrectly uses "it", a pronoun for a single, specific, already-fully-identified referent, not a substitute for "several new instances of a category" — "it" cannot pluralize or take modifiers like "more reliable" in this way.
3 / 26
Which sentence demonstrates a case where "one" substitution is NOT appropriate, and the full noun (or no substitute) should be used instead?
Option C is the incorrect substitution: "the client expects one" is ambiguous and unnatural because "JSON" here is used as an uncountable mass/format noun in this context (referring to a data format, not a countable single item), so "one" does not felicitously substitute for it — the correct sentence would be "the client expects it" (referring back to the JSON response) or restate the noun ("the client expects a JSON response"). Options A, B, and D all correctly use "one" to replace a clearly countable singular noun already established in context (library, algorithm, version) that is being contrasted or modified. "One" substitution works well for countable nouns with a modifier or determiner, but not for uncountable/mass nouns or abstract references like a data format used generically.
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Which sentence correctly uses "the one" (with a definite article) versus "one" (indefinite) to refer back to a specific, previously identified item?
"The one" is used with a definite article when referring to a specific, identifiable member of a previously mentioned set, especially when followed by a defining relative clause ("that failed CI"). Option A is correct: "the one that failed CI" picks out the single specific branch matching that description. Option B is ungrammatical — "a" and "the" cannot both function this way; "a one" is not standard usage in this pattern. Option C ("one that failed") lacks the definite article, which changes the meaning to something closer to "some unspecified branch", losing the sense of picking out the single, specific branch already implied by the singular verb "was" later in the sentence. Option D incorrectly pluralizes to "ones" while the rest of the sentence (singular verb "was") requires a singular referent — a number-agreement mismatch.
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Which sentence correctly avoids using "one" where simple ellipsis (omitting the noun entirely) is more natural in technical English?
When two parallel noun phrases share the same head noun in a list or coordination, English often prefers simple ellipsis (dropping the repeated noun entirely) over inserting "one". Option B is correct and most natural: "staging and production" (both understood as "environments"), with the shared noun omitted rather than substituted. Option A incorrectly attaches "one" only to the second item, creating an asymmetric, awkward construction. Option C is grammatical but unnecessarily wordy and slightly odd-sounding for a simple list — "one" substitution is more natural when a modifier distinguishes the items (as in earlier examples: "a new one", "more reliable ones") than in a plain coordinated list like this. Option D adds definite articles that are not appropriate for introducing a list of environment types generically.
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Code Review Comment: 'I've merged this PR. The issue with the authentication flow was resolved by updating the user_id field. Let me know if you need any further clarification.'
Which sentence best reflects a more concise and professional way to phrase this feedback, using 'one' substitution appropriately?
The original sentence unnecessarily repeats 'issue'. Using 'one' correctly here avoids redundancy. Option 3 rephrases the action and the object of the change in a more standard technical description. Options A and B are overly verbose while option D includes unnecessary phrasing.
7 / 26
Slack Message: 'Hey team, we're seeing a spike in error rates related to the payment_gateway. Initial investigation suggests it might be due to a recent change in the API integration. Can someone investigate further?'
Which of the following options best demonstrates the correct use of 'ones' in this message?
The correct usage of 'ones' is when referring to multiple instances of the same plural noun. The question refers to multiple payment gateways. Options B and C are grammatically incorrect and nonsensical. Option A incorrectly uses 'ones' in a redundant way and option D avoids using 'ones' altogether, which isn't appropriate here.
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PR Description: 'This PR implements the new logging functionality. It uses the log4j library and adds a new logger for tracking user activity.'
Which sentence demonstrates a situation where using 'one' substitution is inappropriate, and the full noun should be used instead?
While 'one' substitution is useful for avoiding repetition, it's inappropriate when describing a specific component or technology. Saying 'It uses log4j' clearly identifies the specific logging library being utilized. Options A and B are redundant, while option C incorrectly substitutes 'one' for 'log4j'.
Which sentence best demonstrates a scenario where simple ellipsis (omitting the noun entirely) is more natural and appropriate than using 'one' substitution?
When describing an API response, it's common to omit redundant words like 'one' or 'details' when the meaning is already clear from the context. Saying 'The API returned the user details' concisely conveys the same information as using 'one'. Options A and B are overly verbose, while option D is unnecessarily complex.
10 / 26
Code Review Comment: 'I've merged this PR. The issue with the authentication flow was resolved by updating the user_id field. Let me know if you need any further clarification.'
Which sentence best reflects a more concise and professional way to phrase this feedback, using 'one' substitution appropriately?
The original sentence unnecessarily repeats 'issue'. Using 'one' correctly here avoids redundancy. Option 3 rephrases the action and the object of the change in a more standard technical description. Options A and B are overly verbose while option D includes unnecessary phrasing.
11 / 26
Slack Message: 'Hey team, we're seeing a spike in error rates related to the payment_gateway. Initial investigation suggests it might be due to a recent change in the API integration. Can someone investigate further?'
Which of the following options best demonstrates the correct use of 'ones' in this message?
The correct usage of 'ones' is when referring to multiple instances of the same plural noun. The question refers to multiple payment gateways. Options B and C are grammatically incorrect and nonsensical. Option A incorrectly uses 'ones' in a redundant way and option D avoids using 'ones' altogether, which isn't appropriate here.
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PR Description: 'This PR implements the new logging functionality. It uses the log4j library and adds a new logger for tracking user activity.'
Which sentence demonstrates a situation where using 'one' substitution is inappropriate, and the full noun should be used instead?
While 'one' substitution is useful for avoiding repetition, it's inappropriate when describing a specific component or technology. Saying 'It uses log4j' clearly identifies the specific logging library being utilized. Options A and B are redundant, while option C incorrectly substitutes 'one' for 'log4j'.
Which sentence best demonstrates a scenario where simple ellipsis (omitting the noun entirely) is more natural and appropriate than using 'one' substitution?
When describing an API response, it's common to omit redundant words like 'one' or 'details' when the meaning is already clear from the context. Saying 'The API returned the user details' concisely conveys the same information as using 'one'. Options A and B are overly verbose, while option D is unnecessarily complex.
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Code Review Comment: 'I've merged this PR. The issue with the authentication flow was resolved by updating the user_id field. Let me know if you need any further clarification.'
Which sentence best reflects a more concise and professional way to phrase this feedback, using 'one' substitution appropriately?
The original sentence unnecessarily repeats 'issue'. Using 'one' correctly here avoids redundancy. Option 3 rephrases the action and the object of the change in a more standard technical description. Options A and B are overly verbose while option D includes unnecessary phrasing.
15 / 26
Slack Message: 'Hey team, we're seeing a spike in error rates related to the payment_gateway. Initial investigation suggests it might be due to a recent change in the API integration. Can someone investigate further?'
Which of the following options best demonstrates the correct use of 'ones' in this message?
The correct usage of 'ones' is when referring to multiple instances of the same plural noun. The question refers to multiple payment gateways. Options B and C are grammatically incorrect and nonsensical. Option A incorrectly uses 'ones' in a redundant way and option D avoids using 'ones' altogether, which isn't appropriate here.
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PR Description: 'This PR implements the new logging functionality. It uses the log4j library and adds a new logger for tracking user activity.'
Which sentence demonstrates a situation where using 'one' substitution is inappropriate, and the full noun should be used instead?
While 'one' substitution is useful for avoiding repetition, it's inappropriate when describing a specific component or technology. Saying 'It uses log4j' clearly identifies the specific logging library being utilized. Options A and B are redundant, while option C incorrectly substitutes 'one' for 'log4j'.
Which sentence best demonstrates a scenario where simple ellipsis (omitting the noun entirely) is more natural and appropriate than using 'one' substitution?
When describing an API response, it's common to omit redundant words like 'one' or 'details' when the meaning is already clear from the context. Saying 'The API returned the user details' concisely conveys the same information as using 'one'. Options A and B are overly verbose, while option D is unnecessarily complex.
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A developer writes in their PR description: 'This commit introduces a new feature for user authentication. It utilizes the OAuth 2.0 protocol and integrates with Google's identity services.' Which sentence best demonstrates an appropriate use of 'one' substitution here?
Insufficient: Options A and D are too informal and use 'one' inappropriately. Option C is technically correct but lacks the specific detail of referencing a previously identified feature. The correct answer correctly uses 'one' to refer back to the entire OAuth 2.0 integration described earlier.
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Lead Developer: 'We've identified a performance bottleneck in the user profile API. The dominant factor appears to be inefficient database queries related to fetching associated data. We're investigating options for caching and index optimization.' Which sentence best exemplifies using 'one' substitution appropriately in this context?
Correct – This option uses 'one' correctly to refer back to the specific problem area (the user profile API) while maintaining a degree of technical detail about the underlying cause. The other options are either too vague or unnecessarily repetitive.
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Developer: 'This PR implements a new feature for handling user session management. It utilizes JWT (JSON Web Tokens) and integrates with our existing authentication service. The core functionality involves generating signed tokens upon successful login.' Which sentence demonstrates the most effective use of 'one' substitution in this PR description?
Correct – This option correctly uses 'one' to refer back to the core functionality (session management) while providing sufficient context about the technologies involved. It avoids unnecessary repetition by using 'one' in a precise manner.
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API Response: `{"status": "error", "code": 400, "message": "Invalid request parameters. The 'userId' field must be a positive integer."}` Which sentence best demonstrates the appropriate use of 'one' substitution when describing this API response?
Correct – This option clearly identifies the specific problem (the invalid 'userId' parameter) and provides the relevant technical details from the response. It avoids conversational phrasing and focuses on accurate description of the API error.
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Developer: 'I'm working on improving the performance of the reporting service. I've identified a slow query that's causing significant delays. The issue is with the aggregation logic in the data warehouse. I'm currently optimizing the indexes and rewriting the SQL query.' Which sentence best exemplifies using 'one' substitution during this standup update?
Correct – This option provides a concise summary of the problem and the actions being taken. It correctly uses 'one' to refer back to the specific area (the slow query in the data warehouse) without unnecessary detail, which is appropriate for a standup update.
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During a code review of a new payment processing module, Sarah comments: 'This commit adds support for accepting payments via Stripe. It uses the Stripe API and handles webhook notifications.' Which sentence best illustrates a scenario where using 'one' substitution would be appropriate?
The core issue highlighted is the *single* payment method supported – Stripe. Using 'one' here correctly identifies this limitation. The other options present broader issues (error handling, integration) that aren't directly related to the singular focus of 'one' payment type.
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In a Slack message discussing a recent deployment, Mark writes: 'We deployed version 2.5.1 today. It includes bug fixes for the user login issue and performance improvements to the search functionality.' Which sentence demonstrates a situation where using 'one' substitution is most effective?
The key here is the *specific* version number (2.5.1) and the *two* distinct improvements: bug fixes and performance enhancements. 'One' accurately reflects that these are two separate, defined areas of change. The other options suggest a more general lack of clarity.
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During a standup meeting, David announces: 'I'm working on optimizing the data retrieval process for our analytics dashboard. I've identified a slow query that's causing significant delays – it's related to fetching user activity logs.' Which sentence best reflects a more concise way to communicate this using 'one' substitution?
The core problem is the *specific* slow query. Using 'one' here correctly pinpoints the single bottleneck causing the delay. The other options describe broader goals or impacts without isolating the precise element of the data retrieval process.
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A developer submits a PR with the following description: 'This commit fixes an issue where users couldn't access their profiles. It updates the user_id field in the database and implements new validation logic.' Which sentence best demonstrates a situation where using 'one' substitution is most appropriate?
The central point is the *two* distinct components involved in resolving the issue: updating the database field and implementing validation logic. 'One' accurately reflects that these are two separate, defined actions taken to fix the access problem. The other options present broader aspects of the change without specifying the core elements.
What will I practise in "One/Ones Substitution in Technical English — IT Grammar Exercise"?
Practise using 'one' and 'ones' to avoid repeating a countable noun, choosing between 'one', 'the one', and ellipsis in technical descriptions.
How many exercises are in this module?
This module has 26 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.