Which and that can be used in place of noun subjects that refer to things or animals, or in place of the subject pronouns it or they When which/that refer to the subject, they cannot normally be omitted We never use a subject pronoun and a relative pronoun together to refer to the subject Not * The cat which it caught the mouse* Which and that remain unchanged whether they refer to the singular or the plural
singular This is the photo which/that shows my house
This is the cat which/that caught the mouse plural These are the photos which/that show my house These are the cats which/that caught the mice
Typical defining relative clause with 'which' as subject
Which or that are possible in the relative clause
The tiles fell off the roof They caused a lot of damage The tiles which fell off the roof caused serious damage
Typical non-defining relative clause with 'which' as subject
Which must be used in non-defining clauses that is not possible The Thames is now clean enough to swim in It was polluted for over a hundred years
The Thames which is now clean enough to swim in, was polluted for over a hundred years
Whose' as the subject of a relative clause: people/things
Whose can be used in place of possessive adjectives {my your his her, etc) [> 4.19] It remains unchanged whether it refers to masculine, feminine, singular or plural
masculine He is the man whose car was stolen
feminine She is the woman whose car was stolen
plural masculine They are the men whose cars were stolen
plural feminine They are the women whose cars were stolen
Whose can replace the possessive adjective its This is the house whose windows were broken
The complex sentence relative pronouns and clauses
However, this use of whose is often avoided by native speakers who regard whose as the genitive of the personal who Instead of this sentence, a careful speaker might say
This is the house where the windows were broken Where the context is formal, of which should be used, not whose
It was an agreement the details of which could not be altered
Or of which the details could not be altered
Typical defining relative clause with 'whose' as subject
The millionaire has made a public appeal His son ran away from home a week ago
The millionaire whose son ran away from home a week ago has made a public appeal