Restrictive and Non-Restrictive Relative Clauses

A restrictive relative clause restricts the meaning of the noun or pronoun it modifies; generally, if the clause is removed, the meaning of the sentence becomes unclear or is even lost. A non-restrictive relative clause is less closely tied to the main clause (the rest of the sentence) and has little effect on the meaning of the noun or pronoun it modifies; if it is removed, the sentence is still complete. It can be thought of as something added on, and it is usually separated from the rest of the sentence by commas. Specifically, restrictive and non-restrictive relative clauses differ in the following ways:

• 1. Different form: a restrictive relative clause is not separated from the main clause by a comma, and there is no pause in speech; a non-restrictive relative clause is usually separated from the main clause by a comma, and there is a pause in speech.
• 2. Different function: a restrictive relative clause modifies, restricts and identifies the antecedent, and removing it leaves the sentence incomplete or the concept unclear; a non-restrictive relative clause adds supplementary information about the antecedent, and if it is omitted the sentence is still clear and complete: People who take physical exercise live longer.
     Those who exercise live longer. (Without the clause, the sentence loses its meaning.)

His daughter, who is in Boston now, is coming home next week. His daughter is in Boston now and will be back next week. (Without the clause, the sentence is still complete.)

• 3. Different translation: when translating relative clauses into Chinese, a restrictive clause is usually placed before the antecedent it modifies, while a non-restrictive clause is translated separately from the main clause: He is the man whose car was stolen. He is the one who had his car stolen.

I’ve invited Jim, who lives in the next flat. I invited Jim; he lives next door.

I invited Jim; he lives next door.

• 4. Different meaning. Compare: I have a sister who is a doctor. I have a sister who is a doctor. (I have more than one sister.)

     I have a sister, who is a doctor. I have a sister, and she is a doctor. (I have only one sister.)

• 5. Different antecedents: the antecedent of a restrictive relative clause can only be a noun or pronoun, whereas the antecedent of a non-restrictive relative clause can be a noun or pronoun, or a phrase or a whole sentence. In addition, when the antecedent is a proper noun or something else unique:

Peter drove too fast, which was dangerous. Peter drove very fast, which was dangerous. (which refers to drove too fast) He changed his mind, which made me very angry. He changed his mind, which made me angry. (which refers to the whole main clause) Mr. Smith, who is our boss, will leave for Japan Our boss, Mr. Smith, is going to Japan next week. (The antecedent is a proper noun, so a non-restrictive relative clause must be used.)

Her father, who has a lot of money, wishes her to study abroad. Her father is rich and wants her to study abroad. (The antecedent is a common noun with a unique referent, so a non-restrictive relative clause must be used.)

• 6. Different relative words: the relative words that and why can be used in restrictive relative clauses but are usually not used in non-restrictive ones; in addition, the relative word can sometimes be omitted in a restrictive relative clause, but it is never omitted in a non-restrictive relative clause.