Relative clauses, commas and agreement

Two kinds of relative clause

Defining (no commas) tells you which one: The cousin who lives in Hue is a nurse. (I have more than one cousin.)

Non-defining (commas at both ends) adds extra information: My cousin, who lives in Hue, is a nurse. (I have one cousin; the clause is an aside.)

Use which for things, who for people, and whose for possession — including possession by a thing: The book whose cover was torn. Never use ‘that’ in a non-defining clause.

Agreement when the subject is long

• The number of applicants has risen. (a number of applicants have risen)
• Each of the students has a locker.
• Neither the teachers nor the head was aware — the verb follows the nearest subject.
• Information, evidence, advice, equipment, research are uncountable: no plural -s, no ‘an’, singular verb.

Dangling participles

The subject after the comma must be the one doing the -ing action.

✗ Walking home, the storm broke overhead. (the storm was not walking)
✓ Walking home, we were caught by the storm.