In English defining relative clauses are introduced by relative pronouns. A defining relative clause cannot be omitted because it adds an essential specification to the noun which otherwise wouldn’t be clear.

A defining relative clause usually follows a noun and it helps to understand whom or what the noun refers to. (E.g. The thief that robbed the lady wore a helmet; The bus that broke down was travelling along Oxford street). There is no comma between the noun and the relative clause.

Subject Pronouns Object pronouns Possessive pronouns Examples
Who who/whom whose
  • The lady who (that) sold the house was 42.
That that  
  • The boy whose father was very ill was Irish.
which which whose/of which
  • The ball that I gave you was Paul’s.
that that  
  • The bike whose brakes I broke is yours.
  • The bike of which I broke the brakes.
Defining relative clauses