A relative clause adds information about a person or thing. It can help you combine related details, but it should leave the reader clear about what the clause refers to and whether it identifies a particular person or adds extra information.
The sentence-structure section in Jobin Thomas’s Premium Grammar for OET Pharmacy Writing explains defining and non-defining relative clauses. This guide uses original administrative examples to practise those distinctions without giving medication advice.
Use the clause to identify the intended noun
In “The form that arrived yesterday needs a signature,” the relative clause identifies which form you mean. It is part of the information needed to select that form from others. There are no commas around it.
This is often called a defining relative clause. The important question is practical: does the clause tell the reader which person or thing the sentence concerns?
Separate additional information with commas
In “The revised form, which arrived yesterday, needs a signature,” the context already identifies the revised form. The clause adds information about its arrival. The commas mark that additional detail.
Original meaning comparison
Identifying a group: “The documents that need signatures are on the desk.”
Adding information: “The documents, which need signatures, are on the desk.”
The first selects the documents needing signatures. The second says that the identified documents need signatures. Adding commas can therefore change the scope of the statement.
Choose who, which or whose for the relationship
“Who” commonly refers to people: “The administrator who called yesterday will send the form.” “Which” refers to things: “The form, which has two pages, is attached.” “Whose” expresses possession: “The learner whose address changed contacted the office.”
Check the clause after choosing the relative word. “The administrator who she called” means something different from “the administrator who called.” An extra pronoun can change the grammatical relationship or produce an error.
Repair the duplicated subject
Draft: “The administrator, who she confirmed the time, will send a message.”
Repair: “The administrator, who confirmed the time, will send a message.”
Here “who” is already the subject of “confirmed.” Adding “she” creates a duplicated subject. The main clause remains “The administrator will send a message.”
Keep the reference close and unambiguous
A long sentence may place several possible nouns before “which.” If the reader could reasonably attach the clause to the wrong one, move it closer to the intended noun or use a separate sentence.
Do not use “which” to introduce a conclusion the information does not support. Combining two observations should not turn them into proof that one caused the other. Grammar should clarify the relationship rather than invent it.
Keep a complete main clause
Temporarily remove an additional relative clause and read what remains. “The form, which arrived today, needs a signature” leaves “The form needs a signature.” That main clause is complete.
By contrast, “The form, which arrived today” leaves the reader waiting for the main statement. In ordinary formal prose, complete the sentence instead of treating the relative clause as a replacement for the main verb.
For your next practice paragraph, check each relative clause for its reference, purpose and punctuation. Explore OET Grammar — Course 17 for the course connected to this pharmacy workbook. Personalised OET sessions can also be requested at dates and times around your shifts, with your tutor confirming the arrangement.
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OET Grammar — Course 17
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Source: OET Pharmacy Gra 01.epub, Jobins Training. Examples labelled original or illustrative were written for this article. Independent exam preparation; no affiliation with or endorsement by the examining body. Practice does not predict an official score.