Yours is a tough but very important grammar question that has never been asked in this Forum. There’s therefore no doubt in my mind that English learners and teachers alike will benefit from a discussion of the subject, so I’m making sure that my answer to your question is as instructive and comprehensive as I can make it.
What is a Substantive Clause?A
substantive clause is an entire clause that serves as the subject or object of a verb. Such clauses are introduced by the relative pronouns “that” and “who” or by the interrogative words “why,” “where,” and “when.”
SUBSTANTIVE CLAUSES
Here are some examples of substantive clauses:
(1) Substantive clause in a statement: “Despite his acquittal, many believe
that the accused is guilty.” Here, “that the accused is guilty” is the substantive clause, functioning as direct object of the verb “believe.”
(2) Substantive clause in a command: “King Herod decreed
that all first-born males be killed.” Here, “that all first-born males be killed” is the substantive clause, functioning as direct object of the verb “decreed.”
(3) Substantive clause in indirect questions: “She inquired
where the residence of the village chief might be.” Here, the question “where the residence of the village chief might be” is the substantive clause, functioning as direct object of the verb “inquired.”
What is an Attributive Clause?On the other hand, an
attributive clause is an entire clause that adds more information about a noun; in other words, the clause serves as a modifier of that noun. An attributive clause can either be restrictive or nonrestrictive.
ATTRIBUTIVE OR ADJECTIVE CLAUSES
Restrictive attributive clauses serve to specify precisely which noun is being referred to. For restrictive attributive clauses, the relative pronoun “that” is used, never “which” (at least in American English); when the antecedent noun is a person, the relative pronoun “who” is used.
Here are examples of attributive clauses:
(1) Restrictive attributive clause: “She liked the laptop
that she saw in the computer shop last night.” Here, “that she saw in the computer shop last night” is the restrictive attributive clause and it modifies the noun “laptop.”
(2) Restrictive attributive clause (for a person as antecedent noun): “The writing contest winner was the young girl
who wrote about a thin, beardless Santa Claus.” Here, “who wrote about a thin, beardless Santa Claus” is the restrictive attributive clause and it modifies the noun “girl.”
Nonrestrictive attributive clauses provide more information about the antecedent noun, but it’s presumed that the specific noun being referred to is already known by the reader either by context or logic. For nonrestrictive attributive clauses, the relative pronoun “which” (never “that”) preceded by a comma is used; when the antecedent noun is a person, the relative pronoun “who” is used. A nonrestrictive attributive clause is optional to the sentence; the sentence will remain grammatically and structurally sound without it.
Here are examples of nonrestrictive attributive clauses:
(1) Nonrestrictive attributive clause: “Many people from the provinces flock to Manila
, which is the capital of the Philippines.” Here, “which is the capital of the Philippines” is the nonrestrictive attributive clause, modifying the antecedent noun “Manila.”
(2) Nonrestrictive attributive clause (for a person as antecedent noun): “Let us all congratulate Mr. Roberto Cruz
, who as we all know has topped the medical licensure exam.” Here, “who as we all know has topped the medical licensure exam” is the nonrestrictive attributive clause, modifying the antecedent noun “Mr. Roberto Cruz.”
I hope that this discussion has adequately clarified the distinction between substantive clauses and attributive clauses for you.
