Defining and Non-Defining Relative Clauses

Grammar Tutorial

Defining and Non-Defining Relative Clauses


Many of my students have a hard time identifying relative clauses, which are typical of academic writing. For many, it is also a problem to tell the difference between defining and non-defining relative clauses or to appreciate the importance of these clauses in reading and in writing.

Sample Problem

What is the difference IN MEANING between the two sentences?

1. She is not particularly fond of politicians, who lie.
2. She is not particularly fond of politicians who lie.


1. Identify the obvious difference between the sentences: the comma.
2. Focus on the clause after the word “politician”: it is a relative clause.
3. Remember your grammar: relative clauses are identified by the presence of a pronoun (“who”) and by their position right after a noun (N.B. Relative clauses are in love with the noun, so they are always right next to it.)
4. Think of the functions of relative clauses: either to clarify which person or object you are referring to or to add an additional comment about something already familiar.
5. So, the first sentence means that she hates all politicians. Explanation: the comment after the statement does NOT specify which politicians she is not fond of; it is just an additional comment about all politicians. The comma is like saying “by the way” or “and”.
6. The second sentence means she is not fond of ONLY THOSE politicians who lie, not all of them. Explanation: the absence of a comma means that the clause clarifies which, of all, politicians she is not fond of.

Conclusion 1: The difference in meaning is significant: in 1. she hates all politicians, but in 2. she does NOT hate all politicians.
Conclusion 2: Knowing relative clauses is knowing how to express yourself efficiently and properly.

About The Author

Grammar And Language Instructor, College Test Prep
I have been an English language instructor for 16 years. I have vast experience teaching TOEFL and SAT classes to international students. I teach all language skills, academic reading and essay writing, speaking, listening and note-taking skills, test-taking techniques, as well as grammar. I am a de...
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