Here we’ve compiled 18 grammar rules on sentence structure which build up from definitions of grammatical terms to practical rules and tips. It can be a lot to learn all at once, but stick with it. By the end, you will have a stronger understanding of how English works, and be able to better communicate your thoughts clearly.
The Importance of Learning Grammar
Grammar can be one of the most frustrating parts of learning a language. Sometimes it feels like you’re expected to memorize countless random rules, and terms that you have no use for. But with the right approach, the patterns and logic of grammar start to reveal themselves – many of the rules actually build off of each other.
That’s essentially what grammar is: the system of rules which structure a language. Grammar is the logic behind the order and choice of our words. With proper grammar, the relationship between the words we use becomes clear, and we can communicate without creating confusion. Even if you choose not to always follow them, knowledge of these grammar rules will help you handle miscommunication.
Basic Grammar Rules: English Sentence Structure
How are English sentences put together? Depending on your native language, you may find English sentence structure simple or quite difficult. Some languages put sentences together much like English does, but others are very different in this regard.
Grammar rule #1: A complete sentence must include a noun and a verb
- Example 1: The bird flew.
In this sentence, the noun is “bird” and the verb is “flew”.
Grammar rule #2: A complete sentence must include a subject and a predicate
The subject refers to the person, place or thing which the sentence is about. The predicate describes the subject, what the subject is doing, or what is being done to it.
In Example 1, the subject is “The bird” and the predicate is “flew”.
As the sentence gets more complicated, it becomes more clear how subject and predicate are different from noun and verb.
- Example 2: The angry bird flew quickly across the sky.
In this sentence, the subject is “The angry bird” and the predicate is “flew quickly across the sky”.
Grammar rule #3: The only exception to the above rules is the imperative sentence
This is a sentence type in which the speaker instructs or commands the person to whom they are speaking. In this type of sentence, only the predicate is required.
- Example 3: Go away!
This is a complete sentence, with a predicate, and no subject.
In an imperative sentence, the subject is implied, because it is the person being instructed.
For instance, Example 3 could be rewritten as follows.
- Example 4: You must go away!
The subject “you” in Example 4 is implied in Example 3, so it isn’t necessary to include.
Grammar rule #4: Adjectives can go directly before the noun they describe, or after it, if separated by a verb
An adjective is a word which describes a noun.
When the adjective is in the subject part of the sentence, it goes directly before the noun.
- Example 5: The angry bird flew.
Like in Example 2, the subject here is “The angry bird”, and it includes both the noun “bird” and the adjective “angry”, which describes it.
But when the adjective is the predicate part of the sentence, it may go after the noun.
- Example 6: The bird is angry.
In this example, the subject is “The bird”, and the predicate is “is angry”. The predicate consists of the verb “is” and the adjective “angry”.
Grammar rule #5: A compound subject includes two or more simple subjects
Compound subjects are created through the use of conjunctions.
Conjunctions are connecting words, like “and”, “or”, and “but”.
- Example 7: The bird and the plane flew.
This sentence contains 2 simple subjects and 1 simple predicate. In other words, the sentence contains a compound subject and a simple predicate. The simple subjects are “The bird” and “the plane”. They are connected by the conjunction “and”. When combined, they form the compound subject “The bird and the plane”.
Grammar rule #6: A compound predicate includes two or more predicates
- Example 8: The bird flew and sang.
This sentence contains 1 simple subject and 2 simple predicates. The simple predicates are “flew” and “sang”. Connected by the verb “and”, they form the compound predicate “flew and sang”.
Grammar rule #7: A compound sentence includes more than one subject or predicate
Example 7 and Example 8 are both compound sentences because they each have more than one subject or more than one predicate.
A compound sentence does not require a compound subject or a compound predicate, however.
- Example 9: The bird sang and the plane flew.
This example of a compound sentence does not include a compound subject or compound predicate. Instead, it consist of two independent clauses.
Grammar rule #8: An independent clause consists of a subject and a predicate, like a complete sentence
In Example 9, the independent clause “The bird sang” is connected to the independent clause “the plane flew” by the conjunction “and”.
Independent clauses are called “independent” because they do not “depend” on any additional words in order to become complete sentences.
A complete sentence must start with a capital letter and end with punctuation.
- Example 10: The plane flew.
In this example, the independent clause “the plane flew” became a complete sentence without any additional words. All that it required was capitalization and punctuation.
Grammar rule #9: A dependent clause cannot form a complete sentence without additional words
A clause is any phrase which includes a noun and a verb. Not all phrases which include a noun and a verb are complete sentences, or independent clauses.
Dependent clauses often contain words like “because”, “which”, “that”, or “when”. In fact, it is often the addition of these words which causes the clause to be “dependent”.
- Example 11: The plane flew when the bird sang.
In this sentence, “when the bird sang” is a dependent clause. As seen above, “the bird sang” is an independent clause. It contains a subject and predicate and can stand alone as a complete sentence. However, “when the bird sang” is not an independent clause. The phrase only makes sense with additional information, and additional words.
- “What happened when the bird sang?”
- “The plane flew.”
Grammar rule #10: The direct object is the noun being acted on by the verb
None of the above examples include a direct object. In each example, the nouns in the sentence perform the verbs in the sentence. For instance, in Example 11, the plane performed flight and the bird performed singing.
The noun which performs the verb is the subject of the verb. The noun “plane” is the subject of the verb “flew” and the noun “bird” is the subject of the verb “sang”.
But many verbs have objects as well as subjects. The object of the verb is the noun which the subject is directing the verb towards.
- Example 12: The bird ate seeds.
In this sentence, the direct object of the verb “ate” is “seeds”. The “seeds” are the noun which “the bird” (the subject) is eating. Without the seeds, the bird would be eating nothing. In other words, the bird is “acting on” the seeds.
Grammar rule #11: The indirect object is the noun which receives the direct object
Some verbs can have direct objects and indirect objects. The indirect object is often connected by words such as “to”, “at”, or “towards”.
- Example 13: The bird gave the seeds to me.
This example has a subject, direct object, and indirect object. The subject is “the bird”, which is the noun performing the verb “gave”. The direct object is “seeds”, which is the object which the bird is “giving”. Without the seeds, the bird would be giving nothing. The indirect object is “me”, connected to the direct object by the word “to”.
It’s not always necessary for the words to be in this order. In fact, this sentence can be formed without the word “to” and still have the same meaning.
- Example 14: The bird gave me the seeds.
Though the order of the words has changed, “seeds” is still the direct object of the verb “gave”, and “me” is still the indirect object.
Grammar rule #12: When written in passive voice, the object of the verb becomes the subject of the sentence
All of the above examples were written in active voice. This means that the order of the sentence is: Subject – Verb – Object. Example 12 is a simple sentence in this structure.
Passive voice refers to phrases where the Object which the Verb is acting on replaces the Subject in the sentence’s structure. The following example is an inversion of Example 12.
- Example 15: The seeds were eaten by the bird.
If we take “eaten” to be the verb of this sentence, then the order of words is Object – Verb – Subject. In this example, the helping verb “were” comes between the Object (seeds) and the Verb (eaten) which is acting upon it.
But because this sentence is in passive voice, the subject of the sentence is “The seeds” and the predicate is “were eaten by the bird”. It’s important to remember the difference between the “subject-predicate” relationship and the “subject-verb-object” relationship.
Grammar rule #13: Conjugations of the verb “to be” are essential to passive voice
Many words are actually versions, or conjugations of the verb “to be”. “Is”, “are”, “was”, and “were” are all versions of it, in addition to words you might expect, like “be”, “being” and “been”.
When a conjugation of “to be” comes before another verb, it is usually an indicator of passive voice. The following example demonstrates how other conjugations of “to be” could function as the helping verb in Example 15.
- The seed was eaten by the bird.
- The seeds are being eaten by the bird.
- The seeds have been eaten by the bird.
- The seeds had been eaten by the bird.
In each of the above example sentences, the meaning is changed by the choice of helping verb. But in all of them, the relationship between the object, subject and verb remains the same.
Grammar rule #14: Sentences written in passive voice can omit the subject of the acting verb
For instance, Example 15 could be rewritten as follows.
- Example 17: The seeds were eaten.
Because the object of the verb “eaten” has become the subject of the sentence, this is a complete sentence with a subject and predicate. The fact that the subject of the verb “eaten” has been removed doesn’t make the sentence incomplete.
Technically speaking, this is because “seeds” is actually the subject of the helping verb “were”.
Grammar rule #15: In passive voice, the subject of the acting verb is connected by a prepositional phrase
Prepositions are words which clarify questions like “where?”, “when?” or “which?” For instance:
- The bird ate seeds under the table.
- The bird ate seeds after lunchtime.
- The bird ate the seeds which I gave him.
The above sentences utilize the prepositions “under”, “after”, and “which”.
In Example 15, the prepositional phrase “by the bird” clarifies the subject of the verb “eaten”.
Grammar rule #16: Prepositional phrases are sometimes separated by commas
- Example 19: The bird, which belonged to my mother, ate seeds.
The prepositional phrase here, which offers additional information, comes in the middle of the sentence and is separated by commas. This is to avoid confusion around sequences such as “my mother ate seeds”.
- After lunchtime, the bird ate seeds.
- The bird, after lunchtime, ate seeds.
These variations on the second sentence from Example 18 move the prepositional phrase “after lunchtime” to the beginning and middle of the sentence.
- Example 21: The seeds under the table were eaten by the bird.
This sentence features two prepositional phrases. “Under the table” clarifies where the seeds were, and the “by the bird” clarifies the subject of the verb “eaten”.
Grammar rule #17: Adverbs function like prepositions
The adverb “quickly” can be moved to the beginning, middle, or end of Example 12.
- Quickly, the bird ate seeds.
- The bird quickly ate seeds.
- The bird ate seeds quickly.
Each of these sentences means the same thing. Adjectives cannot be used so freely.
- The green bird ate seeds.
- The bird ate green seeds.
Grammar rule #18: A subject compliment describes the subject of the sentence
When an adjective doesn’t come directly before the noun it describes, it is a subject compliment. It is connected to the subject by a linking verb, such as “is”.
- Example 24: The bird is green.
This has the same meaning as the phrase “the green bird”, but because it has a subject and predicate, it can function as an independent clause. “The green bird” is only a subject.
Nouns can also be subject compliments.
- Example 25: The bird is a dancer.
Because dancer is a noun, it cannot be placed before the noun the way an adjective can. “The dancer bird” doesn’t make sense as a subject. But when the noun “dancer” is used as a subject compliment, it can describe the bird.
Sentence Structure Rules
Basic English Grammar Rules with Useful Examples