Every language has its own set of structures that native speakers can recognize, parse,^[1] and use to understand and communicate with other speakers of the same language. These structures can change over time as young speakers become old speakers and cultural influences cause the language to shift, and linguists study these structures and write papers describing what they find. What results is a comprehensive description of what you can call the grammar of the language. Some people^[2] see grammar as a set of rules you must follow, while others^[3] see it simply as a description of the current state of the language as it slowly transforms over time. However you choose to see it, it’s important to understand how a particular language functions if you want to effectively communicate with other users of that language.

What follows is a collection of some of the most basic structures in the English language, along with some of the common issues that pop up in student writing. You should keep in mind that the structures and rules included below focus on English being used for academic purposes. Of course, if you’re texting your friends or writing a casual email, not all of the same rules and suggestions will necessarily apply, but you can never go wrong with a good understanding of the basic structure of written English.

What is a sentence?

The sentence is the basic building block for all of the writing you’re going to be doing, so you have to have a firm grip on what they are so that you can produce a lot of good ones. Here’s the definition of a sentence that I usually use with my students:

If we look at that definition, it follows that the most basic sentence typically requires at least two words: a subject and a verb.^[4]

The subject of a sentence is the person, thing or idea that the sentence is about. Any person can be the subject, whether you name them (e.g., Maria or Yousef), describe them (e.g., the director or their nanny), or use a pronoun (e.g., they or we). This makes a lot of sense since people matter to us and do a lot of things, so we see them as subjects quite often. But things can also be talked about, such as animals (e.g., my dog or the buffalos), physical objects (e.g., your phone or his broken shoelace), places (e.g., Boston or the grocery store), or abstract things (e.g., my doctor’s appointment or her speech). Ideas can also be talked about, such as love, cruelty, or confusion.

Verbs can describe either the actions or the current state of the subject. Verbs so frequently describe the actions (e.g., read, wink, or prevaricate) of the subject that many people will define a verb simply as an action. That comes reasonably close to the full meaning of the word, but that’s not all they do. Verbs can also describe the state of the subject, such as when you say, “The soup smells great.” In this sentence, the soup isn’t doing anything, right? Soups can’t check odors with their nose, so that’s not an action it could possibly do. In this case, the verb “smells” describes the state of the soup’s odor. These kinds of verbs are called stative verbs, and there aren’t that many of them, but they are worth noting.^[5]

However, just because you have a subject and a verb together does not necessarily mean that you have a complete thought. Consider this subject and verb: “He gave.” Hopefully, when you read that, your brain should kind of freak out. Why? Because there are all kinds of bits of information missing there. He gave what? He gave it to whom? This sentence, despite having a subject and a verb, is not a complete thought because there are required pieces of information missing. This kind of verb, called a transitive verb, requires an object after the verb.^[6] The object of a verb is the person, place, or thing that the verb acts on, either directly or indirectly. In the case of this example, the direct object could be a gift, a message, a massage, or even a parking ticket. The indirect object is the recipient of the object, so for this example, whomever he gave the thing to would be the indirect object. If we wanted this subject and verb to be part of a complete thought, we would need both a direct and an indirect object. Here’s one way to complete the thought we started earlier: “He gave her the code to his garage.” In this new example, “her” would be the indirect object because she received “the code to his garage,” which is the direct object. Adding those two elements completes the thought created by the subject and verb, meaning that your brain shouldn’t freak out about missing information now.

That, then, is the starting point for our discussion of sentences and sentence structure. Without a subject,^[7] a verb, and a complete thought, you can’t have a sentence. Things get slightly more complicated after that.

Sentence Parts

Sentences can be made of many different parts, so we will start by defining those parts to give us a common reference we can use to talk about how sentences are built. We’re going to start with the super basic and expand from there, so don’t roll your eyes too hard if we cover something you already know.

Words

I’m not going to define what a word is. You already know that. However, I have found that a lot of students don’t really get taught the different types of words that we use to build sentences with, so let’s review what kinds of words we have.

Nouns

Nouns are the things of the universe. We typically think of a noun as a person, place, or thing, but, to be more comprehensive, we should probably add that it can also be an abstract idea.

Verbs

We just reviewed these. Verbs can provide either the action in a sentence or the current state of the subject.

Adjectives

An adjective is a word that modifies a noun by providing additional descriptive information about it. We typically find them in front of nouns, as in “a normal Brit,” but there are plenty of times where we place them after a linking or stative verb, too.

One helpful tip for those that didn’t grow up speaking English—there is a correct order of adjectives when you put several of them together in front of the same noun. There are different categories or types of adjectives, and adjectives of different categories are placed in a specific order that native speakers just absorb as they grow up. That’s the reason that a “beautiful big black cat” sounds right and a “black beautiful big cat” sounds all strange.

This specific order is called the Royal Order of Adjectives,^[8] and while it’s not 100% always correct, you’ll be right far more often than you’re wrong if you stick to it. Here it is:

1. Determiner – These aren’t actually adjectives. These are the little words that go in front of all the adjectives to begin the noun phrase, such as “the,” “an,” “my,” and “those.”
2. Quantity – Numbers are sometimes used as adjectives to describe the quantity of that person, place, or thing that you’re referring to. When used, they go immediately after the determiner and before any other adjectives. However, numbers are not the only words of quantity. You could also use words such as “many,” “few,” and “several” here.
3. Opinion – These are words that provide someone’s opinion or judgment about the noun that you’re modifying. Some of the extremely many adjectives in this category include “belligerent,” “tasteless,” “manic,” “fastidious,” and “nice.”
4. Size – Adjectives related to size include “large,” “miniscule,” and “gargantuan.”
5. Age – Words like “old” and “young” are obvious here, but expressions like “ancient,” “twenty-year-old,” and “newest” count here as well.
6. Shape – Anything that refers to the shape of the thing is part of this group; “square,” “thin,” “angular,” and “spherical” are all good examples.
7. Color – These are obvious, right? You know these: “black,” “violet,” “lime-green,” “puce,” and so on.
8. Origin or Material – Where is it from? “American,” “Malaysian,” “Middle Eastern,” and so on. What is it made of? “Wooden,” “metal,” “stone,” “felt,” or whatever.
9. Qualifier – These are typically nouns that act as modifiers of the actual thing you’re talking about. Examples include “kitchen table,” “office building,” and “video game.” Those nouns should be the closest thing to the noun you’re describing every time.

You obviously don’t have to have an adjective from every category each time you mention a noun, but you could. Most of the time, people don’t use more than three adjectives for any single thing. In addition, you can have more than one of the same category in front of a noun. If you do, though, you should separate them with commas or “and.” Otherwise, if all of the adjectives are from different categories, you don’t need commas between them.

Adverbs

Adverbs are similar to adjectives, except that instead of modifying nouns, they modify how verbs do their actions. For example, you could eat your ice cream “slowly,” “voraciously,” or “hesitantly.” Most adverbs in English end in “-ly,” but not all of them do. You can also walk “fast,” drive “slow,” or paint “well.” Adverbs can also modify adjectives and other adverbs.

Pronouns

A pronoun is a word that takes the place of a previously mentioned or understood noun. Instead of saying “the project” over and over again, you can say the noun once and then use the pronoun “it” to refer to it after that. There are a number of personal pronouns that you use depending on the thing or person you’re replacing and the function they have in the sentence. Here are the ones you use to replace a noun that is the subject or object of a sentence:

There are other pronouns as well, like the impersonal pronouns “someone,” “anyone,” or “no one,” as well as possessives and demonstratives. The important thing to remember is that pronouns don’t mean anything on their own—they just point back to the most recent person or thing that they can connect with, so be careful with how you use them to make sure their antecedents^[10] are clear.

Articles

An article is a tiny word in English that precedes many noun phrases. Examples include “a,” “an,” and “the.”

Prepositions

Prepositions are words that go before nouns and typically show relationships between other nouns. Many prepositions are really tiny words—”at,” “in,” “of,” and “to”—some are a bit longer—”from,” “above,” and “inside” come to mind—and some are fairly long, such as “between.”

Phrases

A phrase is a group of words that work together to create a unit of meaning. In other words, a phrase adds meaning to a sentence. To be a phrase, there must be more than one word, which might seem like an obvious thing to say, but if there’s just one word, then that word is just a noun, or a verb, or a whatever. There are a number of different kinds of grammatical phrases, and most of the ones we’re going to focus on kind of follow the same categories of major word types we just discussed.

Noun phrases

A noun phrase provides additional details or information about a noun and can be used wherever a noun might appear in a sentence.

Verb phrases

Verbs are frequently not just a single word, particularly when the verb tense requires a helping verb or two.

Adjective phrases

An adjective phrase is one that also describes a noun or expands the meaning of an adjective.

Adverb phrases

Adverb phrases do the same work as a single adverb: they modify verbs, adjectives, and other adverbs.

Prepositional phrases

A prepositional phrase begins with a preposition and ends with a noun, though it can have other modifiers in between.

There are other types of phrases, such as infinitive, gerund, and participle phrases. If you’re interested, there are great resources online to help you figure out their structures and uses. Of course, you could also ask your professor, too, and probably have a nice chat.

Clauses

A clause is a group of words with a subject and verb, which is the primary distinction that separates them from phrases. There are two main types of clauses—independent and dependent—but there are many different types of dependent clauses to understand.

Independent clauses

An independent clause is one that can exist independently as a complete sentence. So, any sentence^[11] must also be an independent clause. It can include more than just an independent clause, but it must have at least one independent clause in order to exist as a complete sentence. Here’s a few examples:

Dependent clauses

A dependent clause, then, is a clause^[12] that cannot exist independently as a complete sentence. Typically, dependent clauses are created by the addition of a subordinating conjunction to the beginning of it. Here are some examples of clauses that used to be independent (see the examples above) but that are now dependent because of the addition of the conjunction at the beginning. Note how your brain wants more information when you get to the end of the clause:

In each of these cases, the thoughts that were complete previously are now incomplete. The first example tells us a time when something ended, the second gives us a reason, and the third supplies a condition, but none of these examples here provides us a complete thought now. We require more information in order to make sense of the meaning that started here. Each of these clauses is an example of a dependent-clause type called an adverb clause.^[13]

There are other types of dependent clauses, too. An adjective clause is one that provides additional information about one of the nouns in the sentence and is typically connected to that noun with “that” or “who,” depending on the type of noun you’re referring to.

There are also noun clauses that occupy a place where nouns are usually used in a sentence. These can be identified by a simple test: if you can replace the clause with a noun that maintains the meaning of the original sentence, then it’s a noun clause.

In this example, “what his parents told him when he was younger” is a noun clause, and we can tell because it takes the place where a noun is usually expected in the sentence^[14] and because we can replace it with a noun that basically says the same thing.

Sentence Types

Using different kinds and quantities of clauses, we can build a number of different types of sentences in English. There are only four main types that all sentences fall into.

Simple sentences

A simple sentence is composed of a single independent clause. It can have other phrases attached to it, but it cannot have any other clause.

Compound sentences

“Compound,” when used as an adjective, means that something has been made of two or more things. In this case, a compound sentence is made up of two or more independent clauses. The two independent clauses are joined together by a coordinating conjunction, with a comma separating the two. Here’s what a compound sentence looks like:

In this example, both independent clauses could exist as their own sentences. “Zaphod and Ford went underground” is a complete idea, and so is “Arthur stayed out with Marvin.” Those two clauses are joined together with the coordinating conjunction “but,” with a comma separating the clauses.

In English, there are just a small number of coordinating conjunctions that you can use to join independent clauses together. If you can remember the word “fanboys,” then you can remember the seven coordinating conjunctions:

The most common of these conjunctions are “and,” “but,” “or,” and “so,” so those are the ones you’ll run into the most in both reading and writing, but only those seven words can join two independent clauses together.

Complex sentences

When you join one independent clause with a dependent one, you get a complex sentence. There are many ways to combine these clauses together, so here’s some examples to consider:

Notice that, in the first example, there is a comma after the dependent clause “if you hold a lungful of air” because it comes before the independent clause. In the second example, there is no comma needed because the dependent clause appears after the independent clause. Similarly, when the dependent clause appears at the normal place in the sentence, there’s no comma used.

Compound complex sentences

A compound complex sentence is a combination of the two previous types. These sentences have at least two independent clauses joined by a coordinating conjunction, with at least one dependent clause as well. All the previous rules apply here in terms of punctuation:

Common sentence problems

With rules and structures in place, it’s natural that we might struggle at times to follow them all completely. This can lead to errors in sentence construction, which can make it harder for readers to understand what you’re trying to say to them. So, let’s take a look at the most common issues students run into so you can try to avoid them.

Run-on sentences

One of the most common mistakes students make is not ending their sentences where they need to finish. This produces a run-on sentence, one that “runs on” instead of stopping. Here’s what a run-on sentence can look like.

In this example, there are actually three complete ideas contained within the one sentence, and each of these three ideas should be a complete sentence. The first idea, “I ran right into the living room,” has a subject and a verb, and it is a complete idea. As such, it needs a period at the end of it. Without that period, it’s difficult to recognize the end of that idea and the beginning of the second one, “the TV was on, but no one was watching.” This is actually a compound sentence with two independent clauses. The final idea, “it was kind of creepy,” finally has the period that is missing from all the other sentences.

To fix run-on sentences, you typically need to simply insert periods at the end of the complete ideas. You could also find a way to join up clauses that are related using a coordinating or subordinating conjunction.

Comma splices

Whenever I hear the word “splice,” I’m reminded of the ancient days of yore when we used audio cassette tapes for most of our music. If your tape player ever got fouled up, the tape could get caught in the mechanism. It would pull out and get all tangled, and at the worst of times, it might get wound up so badly, you’d need to break it to get it out. This happened to me once with one of my very favorite cassettes, and I was pretty distraught about it. My aunt showed me how to splice the tape back together by trimming the ends and taping them cleanly together. It saved my tape and my fraught young soul.

A comma splice is not something to save teenagers from angst over lost music, however. A comma splice occurs whenever you try to connect two independent clauses together using just a comma. Here’s what that look like:

In this example, there are two independent clauses. The first one, “Arthur went to the galley to try and find some tea,” is a complete idea all by itself, but instead of ending that sentence with a period, the author put in a comma and then the second independent clause, “he hadn’t had any since escaping the Earth.” We’ll discuss punctuation a bit later, but commas are not used to join things together—they are separators. Using a comma between two independent clauses is just like a run-on sentence except there’s a little more effort involved.

To fix this, you need to find a way to either separate or properly connect the two clauses, just like a run-on sentence. Here are a couple of ways to fix the previous example:

Fragments

Just like the name suggests, a sentence fragment is just a piece of a sentence instead of the whole thing. A sentence fragment starts with a capital letter and ends with a period, but it does not contain a complete sentence for one reason or another. Some fragments are missing a subject, some don’t have a verb, still others don’t have a complete idea, and still others are made dependent by the addition of a subordinating conjunction. Here are some examples:

The thing about fragments is that they’re incredibly easy to put into writing because we use them when we speak. All the time.^[15] However, writing is not the same as speaking, so we can’t follow the same rules when we write as when we speak. We have to be more careful about what we write because of the kind of writing that we are producing: formal, academic work.

To correct a fragment, you need to figure out what is missing or where it belongs. You might need to combine the fragment with another sentence you’ve already written, or you may have to add missing subjects or verbs. You may even need to completely revise the fragment so you can construct a whole thought.

Occasionally, in more informal or conversational writing, fragments can be used to make the writing imitate the usual patterns of speech, but on the whole, you should work to make your writing as comprehensible and complete as possible.