Though most people don’t think about them on an individual level, clauses and phrases join to form every sentence we write and read. While parts of speech are the building blocks of the English language, clauses and phrases work together to connect ideas and give them proper flow and readability. In short, their structure helps us make sense of those ideas. In fiction (and even nonfiction), knowing how to manipulate clauses and phrases are essential to good writing. Without them, sentence variation wouldn’t exist. So let’s start with the basics.
What Is a Clause?
Clauses are groups of related words that have a subject and a verb. Some clauses are dependent, and others are independent. Clauses also help determine when and where commas are needed.
Independent Clauses Independent clauses include a subject and a verb, and they express a complete thought. In other words, they can stand alone.
Example: The cat sat on the windowsill.
Dependent or Subordinating Clauses Dependent clauses also contain a subject and a verb—though they don’t always directly state both (see Example B)—but they do not express a complete thought and are reliant on independent clauses to support them. In other words, they cannot stand on their own and are not sentences.
Example A: When traveling to another country… Example B: …but didn’t show up until 9 p.m. (In the last example, the subject would be implied from the independent clause preceding it; however, since it is not directly stated in the second part, that part is considered a dependent clause, and NO COMMA is used before it.)
Dependent clauses are also the trickiest clauses to master, particularly when it comes to punctuation, because there are several different types.
Relative Clauses (Adjective Clauses) Relative clauses begin with a relative pronoun and function as an adjective. They can be restrictive or nonrestrictive depending on the context.
Restrictive relative clauses are essential to the meaning of the sentence and are NOT set off with commas. They can specify which item/person is being referred to out of several choices, or they can provide information that is crucial to the surrounding clauses.
Example A: The cashier who checked me out at the grocery store was very friendly. In the above example, the relative clause is considered restrictive because it specifies which of the many cashiers working there the sentence is referring to; therefore, no commas are used.
Example B: The television that he chose was one of the most highly rated ones of the year.
In Example B, the restrictive relative clause dictates which television the information following it is discussing. Another very important thing to note about this example is the use of the word that. The word which would actually be incorrect here; it is primarily used for setting off nonrestrictive relative clauses. Grammar Girl has some great tips on the topic.
Nonrestrictive relative clauses are not essential to the meaning of the sentence and could be left out without changing the overall meaning. This type of relative clause is ALWAYS set off with commas.
Example A: Jack, who is our new biology teacher, will be starting next week.
The relative clause in the above example actually tells us two things. First, it tells us that Jack is the new biology teacher, an added detail that is nice to know but isn’t crucial to the overall meaning of the sentence. However, it also implies that the narrator is referring to a specific Jack that the reader is already aware of, indicated by the surrounding commas. Without the commas, it would be assumed that there is more than one Jack and that it was necessary for the narrator to specify which one he was talking about.
Example B: Blueberries, which are a great source of Vitamin C, are one of my favorite fruits.
Example B includes a relative clause that provides us with extra information about the subject that it modifies, but the information does not restrict the subject in any way, so it is considered nonessential and should be set off with commas. Note the use of the word which here rather than that.
Noun Clauses Noun clauses function are a string of words that function as a noun in the sentence. However, they differ from a noun phrase in the fact that contain both a subject and a verb.
Example A: I don’t remember what I ate for dinner. Example B: The question is whether or not the rope will hold. Example C: The winner will be determined by whoever gets the most votes.
Important note about pronoun cases (who, whom, whoever, whomever): Which pronoun should be used is determined by the role it plays in its own clause, NOT by its relation to the rest of the sentence. Example C illustrates this idea.
Adverbial Clauses (most often referred to as subordinate clauses) Adverbial clauses begin with a subordinating conjunction and answer the question when, how, where, why, to what extent, or under what conditions something happens. They can be found anywhere in the sentence but are most commonly found at the beginning or end. Such clauses used at the beginning of a sentence are followed by a comma. Those found at the end are not, except in cases of extreme contrast.
Example A: While you were busy playing games, I completed my art project. Example B: You need to clean up your room before you can hang out with your friends. Example C: We just purchased a new television, though our budget is tight. (A comma is used in the last example because of a contrasting situation.)
Because is probably the most difficult subordinating conjunction to deal with regarding comma usage. While a comma is always used after it when it starts a clause at the beginning of a sentence, whether or not a comma is required before it at the end of a sentence depends solely on the overall meaning of the sentence. A comma is typically only used for clarification.
Example A: Because we missed the bus, our mom drove us to school. Example B: We went for a walk because it was such a nice day. Example C: I didn’t work today, because I was sick. (The comma in the last example is needed for clarification. Without it, it implies that there might be an alternative meaning that doesn’t really make much sense: that the narrator did work today, not because he was sick, but for some other reason that wasn’t expressed. Many times, the comma before “because” will be required when the first half of the sentence is negated, as was the case in Example C.)