New to Relative clauses?
Read the guide before practising — it explains the rules and examples.
General
Defining vs Non-Defining
About Relative Clauses Exercises
Relative clauses are embedded clauses that modify a noun — they add information about who or what the noun refers to. They are introduced by relative pronouns (who, whom, which, that, whose) or relative adverbs (where, when, why). The grammatical choice between these forms depends on whether the noun refers to a person or a thing, whether the clause is defining or non-defining, and whether the pronoun functions as subject or object. These exercises train all those distinctions from B1 to C2 level.
The most important distinction is between defining relative clauses (also called restrictive clauses) and non-defining relative clauses (also called non-restrictive clauses). A defining clause identifies which person or thing the speaker means — it is essential to the meaning of the sentence and is never separated by commas: The student who failed the exam will retake it next month. A non-defining clause adds extra information about a noun that is already uniquely identified — it is enclosed in commas and can be removed without changing the core meaning: My sister, who lives in London, called me yesterday. Getting this distinction right is essential from B1 upwards.
At higher CEFR levels, exercises extend to contact clauses (omitting the relative pronoun when it functions as object: the book I read instead of the book that I read), the formal use of whom, and reduced relative clauses (replacing a relative clause with a participle: the man arrested by police = the man who was arrested by police). These structures appear frequently in academic and formal writing. For the full grammar rules and examples, see the Relative Clauses theory guides.