Defining vs Non-Defining Relative Clauses in Technical English
5 exercises — master the comma-based distinction that changes meaning in specifications, incident reports, and technical documentation.
0 / 15 completed
1 / 15
Choose the sentence that uses a DEFINING relative clause correctly.
A defining (restrictive) relative clause identifies WHICH item we mean — it is essential to the meaning. It takes no commas. "The microservice that handles payments" tells us specifically which microservice. Option A incorrectly adds commas around a defining clause, which would make it non-defining (implying there is only one microservice). In technical documentation, removing or adding commas around a relative clause changes the meaning entirely.
2 / 15
Which sentence uses a NON-DEFINING relative clause correctly?
A non-defining (non-restrictive) relative clause adds supplementary information about a noun that is already fully identified. It is enclosed in commas and always uses "which" (not "that") for things. Option A is missing commas. Option C incorrectly uses "that" in a non-defining clause — "that" is only used in defining clauses. Option D has incorrect comma placement that breaks the sentence structure.
3 / 15
The team ___ owns the CI pipeline is responsible for the outage. Choose the correct relative pronoun.
"That" is the standard choice when the relative clause is defining and the antecedent is a group or collective noun (not a person individually). "Which" is used for things in non-defining clauses or informally in defining clauses for non-human referents. "Whom" refers to a person as the object of a verb or preposition. "Whose" indicates possession. Here "the team that owns the CI pipeline" correctly uses "that" in a defining clause.
4 / 15
Identify the pair where the use of commas changes the meaning.
This is the key distinction: "The servers that run in Frankfurt are faster" implies some servers run elsewhere and are not as fast — the clause defines WHICH servers. "The servers, which run in Frankfurt, are faster" implies ALL servers run in Frankfurt and all are faster — the clause merely adds information. The comma transforms the meaning. Options B, C, and D are incorrect: commas always have the potential to change meaning in relative clauses, never making them truly optional.
5 / 15
Our lead architect, ___ designed the event-driven system, will present the migration plan.
When the antecedent is a person, use "who" (not "that" or "which") in relative clauses. This is a non-defining clause (note the commas) because "our lead architect" already fully identifies the person. "Whom" would be used if the person is the object of the clause (e.g., "the architect whom we hired"), not the subject. "That" and "which" are used for things, not people. Using "who" here is both grammatically and stylistically correct for professional technical writing.
6 / 15
During a code review of the user_authentication module, Sarah comments: 'The error message returned by the API is vague. It only says 'Invalid credentials', but we need to include more context—specifically, which field caused the failure.' Which sentence best reflects Sarah's feedback and correctly uses a relative clause?
This question tests understanding of non-defining relative clauses providing extra detail. Option 2 correctly uses a non-defining clause to elaborate on the API's behavior, mirroring Sarah's feedback. Options 1 and 3 use defining clauses which are less appropriate here as they don't add new information about the API itself; option 4 is too general. The core issue is that Sarah wants to *describe* the API response, not simply state a general rule.
7 / 15
In a Slack channel discussing performance issues with the new microservice, David writes: 'The database queries are slow because the schema was designed by Mark before he left. He didn't consider the expected load.' Which sentence demonstrates correct use of a non-defining relative clause?
This question focuses on the specific use of non-defining relative clauses to provide context about a person's actions. Option 1 accurately uses a non-defining clause to explain *why* the database queries are slow, referencing Mark's previous design. Options 2 and 3 incorrectly use defining clauses, implying that the schema itself is the cause of the problem. Option 4 is too simplistic.
8 / 15
During a PR review for the new payment gateway integration, you notice the developer uses this sentence: 'The transaction ID, tx_12345, was generated by the system.' Rewrite this sentence using a non-defining relative clause to provide more context about the transaction ID.
This exercise tests the ability to construct a correct non-defining relative clause. The addition of 'which is' correctly introduces the relative clause and provides the specific value of the transaction ID. Options 2 and 3 are grammatically incorrect, while option 4 is too informal for a PR description.
9 / 15
In a standup meeting, the team lead asks: 'What progress did you make on implementing the new rate limiting feature?' Alex responds: 'I've been working with the documentation and the API endpoints. The /api/v1/users endpoint returns data in JSON format.' Which sentence demonstrates the correct use of a defining relative clause?
This scenario tests the difference between defining and non-defining clauses. Option 2 correctly uses a *defining* relative clause to *define* what the /api/v1/users endpoint does – it's essential information for understanding the context of the discussion. The other options use non-defining clauses that add extra details, which isn't necessary here.
10 / 15
You are writing a PR description for the new logging service. You want to highlight its key features. Which sentence best uses a non-defining relative clause to provide additional information about the logging service?
This question assesses the ability to use non-defining relative clauses for descriptive purposes. Option 1 correctly provides a key feature of the logging service (automatic capture) without defining it as part of the service itself. The other options either incorrectly use defining clauses or are too general.
11 / 15
During a code review of the user_authentication module, Sarah comments: 'The error message returned by the API is vague. It only says 'Invalid credentials', but we need to include more context—specifically, which field caused the failure.' Which sentence best reflects Sarah's feedback and correctly uses a relative clause?
This question tests understanding of non-defining relative clauses providing extra detail. Option 2 correctly uses a non-defining clause to elaborate on the API's behavior, mirroring Sarah's feedback. Options 1 and 3 use defining clauses which are less appropriate here as they don't add new information about the API itself; option 4 is too general. The core issue is that Sarah wants to *describe* the API response, not simply state a general rule.
12 / 15
In a Slack channel discussing performance issues with the new microservice, David writes: 'The database queries are slow because the schema was designed by Mark before he left. He didn't consider the expected load.' Which sentence demonstrates correct use of a non-defining relative clause?
This question focuses on the specific use of non-defining relative clauses to provide context about a person's actions. Option 1 accurately uses a non-defining clause to explain *why* the database queries are slow, referencing Mark's previous design. Options 2 and 3 incorrectly use defining clauses, implying that the schema itself is the cause of the problem. Option 4 is too simplistic.
13 / 15
During a PR review for the new payment gateway integration, you notice the developer uses this sentence: 'The transaction ID, tx_12345, was generated by the system.' Rewrite this sentence using a non-defining relative clause to provide more context about the transaction ID.
This exercise tests the ability to construct a correct non-defining relative clause. The addition of 'which is' correctly introduces the relative clause and provides the specific value of the transaction ID. Options 2 and 3 are grammatically incorrect, while option 4 is too informal for a PR description.
14 / 15
In a standup meeting, the team lead asks: 'What progress did you make on implementing the new rate limiting feature?' Alex responds: 'I've been working with the documentation and the API endpoints. The /api/v1/users endpoint returns data in JSON format.' Which sentence demonstrates the correct use of a defining relative clause?
This scenario tests the difference between defining and non-defining clauses. Option 2 correctly uses a *defining* relative clause to *define* what the /api/v1/users endpoint does – it's essential information for understanding the context of the discussion. The other options use non-defining clauses that add extra details, which isn't necessary here.
15 / 15
You are writing a PR description for the new logging service. You want to highlight its key features. Which sentence best uses a non-defining relative clause to provide additional information about the logging service?
This question assesses the ability to use non-defining relative clauses for descriptive purposes. Option 1 correctly provides a key feature of the logging service (automatic capture) without defining it as part of the service itself. The other options either incorrectly use defining clauses or are too general.
What will I practise in "Defining vs Non-Defining Relative Clauses — Grammar Exercises"?
Practise defining and non-defining relative clauses in technical English. 5 advanced exercises with IT context and detailed explanations.
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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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.