Separating Complete Sentences
Complete Sentences
What's a Complete Sentence?
A complete sentence, also known as an independent clause, is a sentence that expresses a complete thought. To qualify as a complete sentence, all a sentence needs is a subject and a main verb. A subject is a noun or pronoun, and a main verb is an action that the subject performs. For example, "The cat sleeps." is a complete sentence because it has a subject (cat) and a main verb (sleeps). Complete sentences, particularly on the SAT, can be much more complex than this by incorporating additional modifiers, but the only criteria it needs to be a complete sentence is a subject and a main verb performed by the subject.
Below we will elaborate on what qualifies as a complete sentence (what counts as a "main verb", etc.), and how to separate or connect complete sentences. The SAT isn't going to test you on any of the terminology (like gerunds, non-essential clauses, etc.), but it's important to understand the concepts. It will help to know the terminology though since we might refer to it when analyzing whether sentences/answer choices are correct.
Not All Verbs Count as Main Verbs
Some words that are typically verbs can become a different part of speech, or fail to qualify as a main verb, depending on how they are used.
Verbs ending in "ing"
Need a helper verb to act as a main verb
When we add "ing" to the end of a verb, it can only act as a main verb if it's preceded by helper verb, often a "to be" verb (e.g. "Tim is helping Mary with her move"). Without a helper verb, an "ing" verb cannot be the main verb in a sentence. It might be a gerund, a present participle, or it might be used to lead off a non-essential clause, as we'll explore below. Here are a few examples of "ing" verbs combined with a helper verb to act as a main verb phrase:
- "The cat is sleeping."
- "The comfort of having close friends next to her made watching the scary movie more tolerable."
- "The lion started running after its prey."
Gerunds (when an "ing" verb acts as a noun)
When an "ing" verb acts as a noun, it's called a gerund. For example, in the sentence "Sleeping is the cat's favorite activity", "sleeping" is used as noun that represents the activity of sleeping. This sentence is complete because "sleeping" is the subject of the sentence and the main verb is "is". Here are a few more examples of gerunds:
- "Reading is a great way to learn."
- "Running helps Jack to stay fit."
- "Joes likes climbing mountains."
Present Participles (when an "ing" verb acts as an adjective)
"ing" verbs can also be used as an adjective, known as a present participle. For example, the phrase "The sleeping cat" is not a complete sentence because "sleeping" is not used as a verb; it is used as an adjective to describe the state of the cat. We could make the sentence complete by adding a main verb, like "The sleeping cat was woken by the squeaking mouse." Here are a few more examples of present participles:
- "It's tough to commute to work without a working car"
- "The dog chased the fleeing squirrel."
- "Anthony was annoyed by the barking dog."
"ing" verbs can begin non-essential clauses
"Ing" verbs can also be used to lead off non-essential clauses, as we saw in the earlier section. For example, "The cat, hoping to finally catch its prey, pounced on the red dot." In that sentence, "hoping to finally catch its prey" is a non-essential clause that is separated from the rest of the sentence by commas, so "hoping" is not a main verb. These non-essential clauses might appear in the middle of a sentence, like we just saw, or they can also be at the beginning of a sentence ("Hoping to finally catch its prey, the cat pounced on the red dot."), or at the end of a sentence ("The cat pounced on the red dot, hoping to finally catch its prey.").
"To" Verbs (aka Infinitives)
When you add the word "to" in front of a verb, it becomes what's known as an infinitive verb, which does not act as a main verb. Depending on the context, it may act as a noun, adjective, or adverb. For example, in the sentence "To err is human", "to err" is an infinitive verb that acts as a noun, representing the act of erring. Also, in the sentence "I need to win", "to win" acts as a noun because it represents a thing that is needed. In the sentence "I went to buy bananas", "to buy" acts as an adverb because it describes the reason the subject "went". An infinitive verb can also act as an adjective, describing a noun. For example, in the sentence "The book to read is on the shelf", "to read" acts as an adjective describing the book.
Ways to Separate or Connect Complete Sentences
There are several ways that you can properly separate or connect two complete sentences, summarized below:
- Periods
- The most common and obvious way to separate two complete sentences is to use a period. For example, "The cat sleeps. The dog barks."
- Semicolons
- For the purposes of the SAT, semicolons can be used interchangeably with periods. Both can be used to separate complete sentences.
- In reality, there is more nuance to deciding whether we would use a semicolon or a period. A semicolon suggests there is a stronger connection between the two sentences. However, the SAT doesn't test you on that level of nuance, so we won't focus on it.
- Semicolons also have a second use, which is to separate items in a list. We'll get into this more in the semicolons section.
- Comma + FANBOYS conjunction
- We can also connect two independent clauses with a comma and a coordinating conjunction. We use the acronym FANBOYS to remember the coordinating conjunctions: for, and, nor, but, or, yet, so. For example, "The cat sleeps, and the dog barks." properly connects two independent clauses (aka complete sentences).
- The comma should be placed before the conjunction. For example, "The cat sleeps and, the dog barks." would not work.
- A comma on its own is not enough to connect two independent clauses. For example, "The cat sleeps, the dog barks." is not a proper sentence. This would be considered a comma splice, which is a grammatical error. We need the coordinating conjunction after the comma to connect the two clauses.
- Colons (sometimes)
- A colon can sometimes be used to connect two complete sentences, but it might also come between a complete sentence and a sentence fragment.
- Whenever a colon is used correctly, there should always be a complete sentence before the colon.
- After the colon, we may have a complete sentence, or we might have a sentence fragment.
- The word "because"
- For example, "I went to the store because I needed milk."
Adjacent Complete Sentences ALWAYS Require One of the Above
It's not just that you CAN use one of the above to connect two complete sentences; when there are two complete sentences next to each other, you MUST use one of the above to connect them. Otherwise, there is some grammatical error such as a run-on sentence or a comma splice.