What is a Clause in Grammar?

In grammar, a clause is a group of words that contains a ‘subject’ and a ‘predicate’, and functions as a complete sentence or as a part of a sentence. Clauses are the building blocks of sentences and can express a complete thought.

What is a predicate?

A predicate is an essential component of a sentence that provides information about the subject. It expresses the action, state or condition of the subject. The predicate can be the verb or verb phrase alone, but it typically includes other elements such as objects, complements or modifiers.

The predicate can be divided into two main parts: the main verb and any accompanying elements:

• She reads a lot of nonsense.

In this sentence, the subject is ‘she’, and the predicate is ‘reads a lot of nonsense’. The main verb is ‘reads’, and it expresses the action or activity of the subject. But, as can be seen, the predicate may also contain elements in addition to the verb.

Here is an example of a predicate containing complements, modifiers and objects:

• She baked a delicious chocolate cake for her friend’s birthday.

In this lengthier sentence, the subject is ‘she’, and the predicate is ‘baked a delicious chocolate cake for her friend’s birthday’. The breakdown of the predicate is as follows:

• Verb = baked. This is the main verb that indicates the action.
• Object = a delicious chocolate cake. This is the direct object of the verb ‘baked’. (The direct object receives the action of the verb.)
• Complement = for her friend’s birthday. This is a prepositional phrase that acts as a complement. It provides additional information about the purpose or recipient of the action. Specifically, this complement answers the question: for whom or for what reason did she bake the cake?
• Modifier = delicious. This is an adjective that modifies the noun ‘cake’. It describes the quality of the cake.

So, to put it simply, the predicate of a clause can contain multiple complements and modifiers and is not merely a verb or verb phrase alone as can be incorrectly supposed. The predicate is a vital part of a sentence that includes the verb and any accompanying elements, providing information about the subject and expressing the action, state or condition.

What is the difference between a phrase and a clause?

As stated at the beginning of this article, a clause is a group of words that contains a subject and a predicate, and a clause can stand alone or function as a part of a sentence. A clause can express a complete thought and has a subject and predicate combination, as exemplified above.

The main difference between a clause and a phrase lies in their function within a sentence. A phrase is a group of words that does not contain a subject and a verb combination. A phrase functions as a unit within a sentence, but it does not express a complete thought and neither can it stand alone or exist as a sentence.

Phrases are used to provide additional information, modify nouns or verbs, or serve other grammatical functions:

• In the morning

This example of a phrase is a prepositional phrase that provides information about the time, but does NOT contain a subject and a verb.

Phrases can also be categorised based on their structure and function. Examples are noun phrases, verb phrases, prepositional phrases, adjective phrases and adverbial phrases. Phrases are classed according to the parts of speech that lead the phrase.

The key difference is that a clause contains a subject and a verb, while a phrase does not have a subject-verb combination.

Types of clauses

There are different types of clauses too, and these are based on their function within a sentence.

An independent clause, frequently referred to as the ‘main clause’ of a sentence, can exist as a sentence in its own right because it expresses a complete thought and does not rely on any other clauses for its meaning. An independent clause contains a subject and a predicate and can also be called a sentence:

• I went shopping yesterday.

A dependent clause, often called the ‘subordinate clause’, cannot stand alone as a complete sentence in its own right because it relies on an independent clause, or on being a part of a sentence, to provide a complete thought. Dependent clauses often begin with subordinating conjunctions or relative pronouns.

The following are some examples of dependent clauses in bold with the independent clauses in brackets:

•  Adverbial clause = Although I studied hard, (I didn’t pass the exam).
• Adjective clause = (The book) that I borrowed (is on the table).
• Noun clause = What she said surprised me. The clause ‘what she said’ acts as the direct object of the verb.

Dependent clauses can serve various purposes within a sentence and can operate as adverbial clauses, adjective clauses or noun clauses based on their role. A sentence can contain multiple clauses, both independent and dependent, and these can be combined to form complex sentences.

Relative clauses

Relative pronouns are among the main types of pronouns in English; each serving a specific purpose in replacing nouns and making sentences more concise and coherent. Relative pronouns are used to introduce a relative clause, which is a type of subordinate clause that provides additional information about a noun or pronoun in the main clause of a sentence. Relative pronouns connect the relative clause to the main clause and help to join the two together, as shown in the example of the adjective clause above.

As seen in each example below, the subordinate clause, in this case a relative clause because it contains a relative pronoun, can appear in two ways: either at the end of the sentence or sandwiched into the middle:

• I love the book, which was written by David Smith.
• David Smith wrote the book, which I love.
• The book, which I love, was written by David Smith.

For more details on relative pronouns, please see the relevant post.

Relative pronouns not only introduce the relative clause but also function as the subject, object or possessive pronoun within that clause. They help to combine two ideas or provide more information about a specific person, thing or place.

Punctuation, defining clauses and non-defining clauses

Notice in the section on relative clauses above that before using ‘which’, a comma has been placed. If one were to write the same sentence with the pronoun ‘that’, the comma would not be necessary:

• I love the book that was written by David Smith.
• I love the book, which was written by David Smith.

The reason for this is that ‘that’ designates a ‘defining clause‘ and ‘which’ designates a ‘non-defining clause‘.

A defining clause, also known as a restrictive clause, provides essential information about contents of the main clause. Defining clauses do not typically require commas because they are integrated into the sentence structure.

A non-defining clause provides further details on who or what is being described. A non-defining relative clause typically follows a comma because it is added information that is considered non-essential and additional. A non-defining clause is not integral to the structure of the sentence and can potentially be removed.

The choice as to whether or not to use a comma with the relative clause should be based on whether the relative clause provides the reader with additional information, or whether the relative clause is essential to the subject of the sentence.

In practice, the relative pronoun ‘that’ is preferred for defining clauses and ‘which’ is preferred for non-defining clauses.

Conclusion

Grammatical clauses are fundamental units of syntax within sentences. Utilising clauses effectively allows for grammatically correct sentence construction, and recognising the different types of clauses and their functions enhances one’s writing and allows for the creation of more varied and complex sentences.

A main clause is a complete sentence that can stand alone, expressing a complete thought. A subordinate clause, on the other hand, cannot stand alone and depends on the main clause for meaning.

A defining clause provides essential information to identify the noun it modifies and cannot be removed without changing the meaning of the sentence. In contrast, a non-defining clause offers additional, non-essential information and is set off by commas.

If you have any questions or comments, please do add them below.

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https://dictionary.cambridge.org/dictionary/english/