What do you call a group of words with its own subject and verb can either stand by itself or depend on other parts?

Like a phrase, a clause is a group of related words; but unlike a phrase, a clause has a subject and verb. An independent clause, along with having a subject and verb, expresses a complete thought and can stand alone as a coherent sentence. In contrast, a subordinate or dependent clause does not express a complete thought and therefore is not a sentence. A subordinate clause standing alone is a common error known as a sentence fragment.

Independent clauses

He saw her. The Washingtons hurried home. Free speech has a price. Grammatically complete statements like these are sentences and can stand alone. When they are part of longer sentences, they are referred to as independent (or main) clauses.

Two or more independent clauses can be joined by using coordinating conjunctions ( and, but, for, nor, or, so, and yet) or by using semicolons. The most important thing to remember is that an independent clause can stand alone as a complete sentence.

In the following example, the independent clause is a simple sentence.

Erica brushed her long, black hair.

Next, the coordinating conjunction and joins two independent clauses.

Fernando left, and Erica brushed her long, black hair.

Next, a semicolon joins two independent clauses.

Fernando left; Erica brushed her long, black hair.

All sentences must include at least one independent clause.

After she told Fernando to leave, Erica brushed her long, black hair.

In the previous sentence, the independent clause is preceded by a clause that can't stand alone: After she told Fernando to leave.

Erica brushed her long, black hair while she waited for Fernando to leave.

Here, the independent clause is followed by a clause that can't stand alone: while she waited for Fernando to leave.

Beginning sentences with coordinating conjunctions

Any of the coordinating conjunctions ( and, but, for, nor, or, so, and yet) can be used to join an independent clause to another independent clause. Can you begin a sentence with one of these conjunctions?

No one knew what to do. But everyone agreed that something should be done.

An old rule says that you shouldn't. But beginning a sentence with a coordinating conjunction is acceptable today. (Notice the preceding sentence, for example.) Sometimes beginning a sentence this way creates exactly the effect you want. It separates the clause and yet draws attention to its relationship with the previous clause.

Subordinate clauses

A subordinate clause has a subject and verb but, unlike an independent clause, cannot stand by itself. It depends on something else in the sentence to express a complete thought, which is why it's also called a dependent clause. Some subordinate clauses are introduced by relative pronouns ( who, whom, that, which, what, whose) and some by subordinating conjunctions ( although, because, if, unless, when, etc.). Subordinate clauses function in sentences as adjectives, nouns, and adverbs.

Relative clauses

A relative clause begins with a relative pronoun and functions as an adjective.

In the following sentence, the relative pronoun that is the subject of its clause and won the Pulitzer Prize is the predicate. This clause couldn't stand by itself. Its role in the complete sentence is to modify novel, the subject of the independent clause.

The novel that won the Pulitzer Prize didn't sell well when it was first published.

In the next example , which is the relative pronoun that begins the subordinate clause. Celebrities is the subject of the clause and attended is the verb. In the complete sentence, this clause functions as an adjective describing ceremony.

The ceremony, which several celebrities attended, received widespread media coverage.

Note that in a relative clause, the relative pronoun is sometimes the subject of the clause, as in the following sentence, and sometimes the object, as in the next sentence.

Arthur, who comes to the games every week, offered to be scorekeeper.

Who is the subject of the clause and comes to the games every week is the predicate. The clause modifies Arthur.

In the following sentence , mothers is the subject of the clause, adored is the verb, and whom is the direct object of adored. Again, the clause modifies Arthur.

Arthur, whom the team mothers adored, was asked to be scorekeeper.

Noun clauses

A noun clause functions as a noun in a sentence.

What I want for dinner is a hamburger. (subject of the verb is)
The host told us how he escaped. (direct object of the verb told)
A vacation is what I need most. (complement of the linking verb is)
Give it to whoever arrives first. (object of the preposition to)

Pronoun case in subordinate clauses

Who, whom, whoever, whomever. In deciding which case of who you should use in a clause, remember this important rule: The case of the pronoun is governed by the role it plays in its own clause, not by its relation to the rest of the sentence. Choosing the right case of pronoun can be especially confusing because the pronoun may appear to have more than one function. Look at the following sentence.

They gave the money to whoever presented the winning ticket.

At first, you may think whomever is correct rather than whoever, on the assumption that it is the object of the preposition to. But in fact the entire clause, not whoever, is the object of the preposition. Refer to the basic rule: The case should be based on the pronoun's role within its own clause. In this clause, whoever is the subject of the verb presented.

A good way to determine the right pronoun case is to forget everything but the clause itself: whoever presented the winning ticket is correct; whomever presented the winning ticket is not.

The following two sentences show how you must focus on the clause rather than the complete sentence in choosing the right pronoun case.

We asked whomever we saw for a reaction to the play.

We asked whoever called us to call back later.

In each sentence the clause is the direct object of asked. But in the first sentence, whomever is correct because within its clause, it is the object of saw. In the second sentence, whoever is correct because it is the subject of called.

Adverbial clauses

Many subordinate clauses begin with subordinating conjunctions. Examples of these conjunctions are because, unless, if, when, and although. What these conjunctions have in common is that they make the clauses that follow them unable to stand alone. The clauses act as adverbs, answering questions like how, when, where, why, to what extent, and under what conditions.

When Mauna Loa began erupting and spewing lava into the air, we drove away as quickly as we could.

In the preceding sentence , when is a subordinating conjunction introducing the adverbial clause. The subject of the clause is Mauna Loa and the predicate is began erupting and spewing lava into the air. This clause is dependent because it is an incomplete thought. What happened when the volcano began erupting? The independent clause we drove away as quickly as we could completes the thought. The adverbial clause answers the question “When did we drive?”

In the following sentence, because introduces the adverbial clause in which van is the subject and needed the verb. This clause is an incomplete thought. What happened because the van needed repairs? The independent clause The group of tourists decided to have lunch in the village is necessary to complete the thought. Again, the subordinate clause as a whole acts as an adverb, telling why the tourists decided to have lunch in the village.

The group of tourists decided to have lunch in the village because the van needed repairs.