What Is a Clause?
A clause is a group of words containing both a subject (who or what the sentence is about) and a verb (which describes the main action of the subject). There are two kinds of clauses: independent and dependent clauses. Most simply, an independent clause can form a complete sentence on its own and a dependent clause cannot (at least, not by itself).
Think of it this way: an independent clause is like a cup of coffee, and a dependent clause is like a caffeine lover. Caffeine lovers are dependent on coffee, so the two can be joined (quite happily) to form a cohesive unit. Similarly, two cups of coffee, or two independent clauses, can be combined. However, you cannot put two caffeine-dependent people together to form a working unit without any coffee. It just doesn’t work. They need caffeine.
The same is true with sentences. You can join an independent clause and a dependent clause. You can even join two independent clauses (as long as you use proper punctuation and/or a coordinating conjunction). But you can’t stick two dependent clauses together and expect to form a sentence.
Simple enough, right? Let’s go into more detail and look at some examples of independent and dependent clauses.
Independent Clauses
An independent clause contains a subject (again, who or what the sentence is about) and a predicate (which tells us something about the subject, such as what the subject is doing). As mentioned, these clauses can function as their own complete sentences, but they can also be combined with other clauses (either independent or dependent) to create longer sentences. Consider this example:
The coffee was brewing because it was early morning.
We can break this sentence down into two parts. The first part is the coffee was brewing. This is an independent clause because it contains both a subject and a verb: the subject is the coffee and the verb phrase is was brewing. This clause can stand on its own as a complete sentence.
The coffee was brewing.
However, we still have additional information:
. . . because it was early morning.
This is not an independent clause because it lacks a subject. Instead, we have a dependent clause (also called a subordinate clause). Dependent clauses can’t stand alone; that is, they require the support of independent clauses to constitute a complete sentence, just as the coffee lover needs coffee to function.
Joining Independent Clauses
An independent and a dependent clause can be joined to form a single sentence, as you’ve seen in the above example. But can two independent clauses be joined in one sentence? Let’s go back to that delicious cup of coffee. Here is a sentence with one independent clause and one dependent clause.
The coffee was brewing because it was early morning.
Let’s delete because and form two sentences:
The coffee was brewing. It was early morning.
We now have two independent but related clauses, each forming its own sentence. Because the content of these clauses is related, we might want to connect them somehow. How can we do this in a single sentence? Using a semicolon, of course!
The coffee was brewing; it was early morning.
What initially began as a sentence made up of an independent and a dependent clause has become a sentence with two independent clauses. If semicolons aren’t really your style, you can also use a comma and a conjunction to join two independent clauses. Like two cups of coffee poured into one humongous cup, two independent clauses can be joined with little work.
Dependent Clauses
As you’ve already learned, dependent clauses cannot stand alone in a sentence, just as tired people cannot function without coffee. A dependent (or subordinate) clause begins with a subordinating conjunction, such as if, after, before, because, although, or when, and it requires the support of an independent clause to constitute a complete sentence.
There are a few different types of dependent clauses: adjective clauses, adverbial clauses, and noun clauses.
Adjective Clauses
An adjective clause is a dependent clause that describes a noun in another part of a sentence. Usually, an adjective clause is very close to the noun it describes. Adjective clauses begin with the relative pronouns who, whom, whose, that, or which. They can also begin with the relative adverbs when, where, or why.
There’s the café that you’ve been looking for all day.
The subject is the café. Pay close attention to the word that and what follows it. The phrase that you’ve been looking for all day gives us information about or describes the noun café. That means it’s an adjective clause, and because an adjective clause is a type of dependent clause, it cannot stand on its own.
Adverbial Clauses
Adverbial clauses are dependent clauses that tell us why, when, how, or under which conditions something occurs. Look at the following example.
Although you already had six cups of coffee, you decided to buy more coffee anyway.
We know the adverbial clause can’t be you decided to buy more coffee anyway because it can stand alone as a complete sentence. However, the adverbial clause, although you already had six cups of coffee, tells us under what circumstances you decided to buy more coffee. The adverbial clause, which is a dependent clause, needs the independent clause to form a complete sentence.
Noun Clauses
Noun clauses can act as either the subject or the object of a clause, and they usually begin with words like what, why, who, and that.
I don’t care what the doctors say about caffeine intake.
In the first part of the sentence, the subject is I, and don’t care is the verb phrase. The noun clause is what the doctors say about caffeine intake. This clause describes what it is that the subject doesn’t care about and is therefore dependent (like some caffeine-obsessed people I know).
Conclusion
Here’s a brief summary: independent clauses are made up of a subject and predicate, and can stand alone as a sentence. Like cups of coffee, they’re perfect on their own. Dependent clauses are made up of a subject and predicate but cannot stand alone due to the presence of a subordinating word, such as although, if, or because. Dependent clauses are like coffee lovers; they cannot stand on their own. They need coffee!
Dependent clauses can be any of the following: adjective clauses, which describe nouns; adverbial clauses, which tell us why, when, how, or under which conditions something occurs in a sentence; or noun clauses, which act as the subject or the object of a clause and usually begin with words like what, why, who, and that. Dependent clauses need independent clauses like coffee lovers need coffee. Together, they can’t be stopped!