human
What grammar rules do I need to know to correctly use adjective clauses?
assistant
To correctly use adjective clauses, you need to know the following grammar rules: 
1. Adjective clauses are dependent clauses that start with a relative pronoun, such as who, whom, whose, which, or that.
2. The relative pronoun must agree with the noun it is referring to in terms of gender and number.
3. In adjective clauses, the verb must agree with the subject of the clause.
4. Adjective clauses always function as adjectives; they describe the noun that comes before it and adjectives are never separated from the nouns they describe by a comma.