5 exercises — restrictive vs. non-restrictive relative clauses in technical documentation, specs, and ticket writing.
Quick reference
that — restrictive (defines which one): "The function that returns null…" — no commas
which — non-restrictive (adds extra info): "The Auth module, which uses OAuth…" — commas required
who — for people: "The engineer who reviewed this…"
Test: Remove the clause — if the sentence still identifies the right thing → non-restrictive → use which + commas
0 / 5 completed
1 / 5
Which sentence correctly uses a relative clause to describe a specific technical component? "The module _____ handles authentication should be updated to use the new OAuth library."
Both "which" and "that" are correct for restrictive (defining) relative clauses about things. However, there is a subtle preference: in formal technical writing that is standard for restrictive clauses ("The module that handles authentication"), while which — strictly speaking — introduces non-restrictive clauses ("The Auth Module, which handles OAuth, needs updating"). In practice, especially in American English, that is preferred for restrictive clauses. Use who only for people.
2 / 5
Choose the correct relative pronoun. "The developer _____ submitted the PR left detailed comments explaining every change."
Both "that" and "who" are correct for restrictive clauses about people, though "who" is more formal and standard in professional writing. "Which" is used for things, not people — never say "the developer which submitted". In technical documentation: use who for people (the engineer who…), that/which for systems, processes, and things (the function that…, the endpoint that…).
3 / 5
Which sentence correctly uses a non-restrictive relative clause?
Option B is correct. A non-restrictive (non-defining) relative clause adds extra information about something already uniquely identified — set it off with commas. "The authentication service" is already specific (there's only one), so the clause ", which we deployed last Friday," adds context but doesn't define which service we mean. Option A uses a restrictive clause (no commas) — this implies there are multiple authentication services and we need the clause to specify which one. Option C incorrectly uses "who" for a service. Option D uses "where" (for places).
4 / 5
Complete the technical documentation sentence correctly. "The cache layer, _____ is implemented using Redis, reduces database load by approximately 60%."
"The cache layer, which is implemented using Redis, reduces database load by approximately 60%." — This is a non-restrictive relative clause (notice the commas). Use which for non-restrictive clauses about things. The clause ", which is implemented using Redis," adds a detail about an already-identified layer — it doesn't tell us which cache layer, it tells us something about the one we already know. The quick test: if you can remove the clause without changing the core meaning of the sentence, it's non-restrictive → use which with commas.
5 / 5
You're writing a technical spec. Which sentence is correctly punctuated and uses the right relative pronoun?
"Requests that exceed the rate limit will receive a 429 response." — This is a restrictive relative clause: it specifies which requests we're talking about (only those that exceed the rate limit — not all requests). Restrictive clauses: no commas, use that (or which informally). Option B incorrectly adds commas, turning it non-restrictive — this would imply all requests exceed the limit. Option C (no commas, which) is often acceptable in British English but less standard in technical documentation. Option D has mismatched punctuation (opening comma, no closing comma).