In addition to the material on this page, see the post on English Sentence Structure. The Mastering the Mechanics webinar series also describes required sentence elements and varying sentence types.
Key: Yellow, bold = subject; green underline = verb; blue, italics = object; pink, regular font = prepositional phrase
Independent clause: An independent clause can stand alone as a sentence. It contains a subject and a verb and is a complete idea.
Dependent clause: A dependent clause (or subordinate clause) also contains a subject and a verb but is not a complete sentence by itself. It must be attached to an independent clause.
Subject: A person, animal, place, thing, or concept that does the action in the sentence. Determine the subject by asking the question Who or what? Notice that the subject is a noun phrase that may consist of a single word or a group of words.
Verb: Expresses what the person, animal, place, thing, or concept does. Determine the verb in a sentence by asking the question “What was the action or what happened?”
Note: The verb be sometimes acts as a copula or a linking verb, as in the last example above. It links the subject, in this case these findings to its complement, in this case, consistent with those of previous studies.)
Object: A person, animal, place, thing, or concept (noun phrase) that receives the action. Determine the object in a sentence by asking the question Who or what is being acted upon?
Prepositional Phrase: A phrase consisting of a preposition (e.g., in, at, for, behind, until, after, of, during) and the word(s) following it (most often a noun phrase). A prepositional phrase can modify a noun, a verb, an adjective, or even an entire sentence. A prepositional phrase answers one of many questions, for example, Where? When? How? In what way?
For additional resources on parts of speech, see the following posts:
A simple sentence consists of only one independent clause: a subject and a verb, often with an object and modifiers.
Key: yellow, bold = subject; green underline = verb; blue, italics = object
Here are a few basic examples:
Important note about simple sentences: The term simple refers to the clause structure of the sentence (i.e., one independent clause). However, researchers (e.g., Biber et al., 2011) have found, in academic English, that the noun phrases (subject and object) within a simple sentence are usually complex. In other words, in academic writing, a so-called simple sentence is still likely to be rich with information embedded in its noun phrases. Here are a few published examples of simple sentences with complex noun phrases from Biber et al. (2011):
Taking just the main word of the subject, verb, and object from the above examples shows how much valuable information has been packed into the noun phrases:
Biber, D., Gray, B., & Poonpon, K. (2011). Should we use characteristics of conversation to measure grammatical complexity in L2 writing development? TESOL Quarterly, 45(1), 5–35. https://doi.org/10.5054/tq.2011.244483
A compound sentence contains at least two independent clauses. These two independent clauses can be combined using a comma with a coordinating conjunction or using a semicolon.
Key: independent clause = yellow, bold; comma or semicolon = pink, regular font; coordinating conjunction = green, underlined
Here are a few examples:
Using some compound sentences in writing allows for more sentence variety.
A complex sentence contains at least one independent clause and at least one dependent clause. Dependent clauses can refer to the subject (who, which) the sequence/time (since, while), or the causal elements (because, if) of the independent clause.
Key: yellow, bold = independent clause; pink, regular font = comma; blue, italics = dependent clause
Here are a few examples:
Using some complex sentences in writing allows for more sentence variety.
Sentence types can also be combined. A compound-complex sentence contains at least two independent clauses and at least one dependent clause.
Key: yellow, bold = independent clause; pink, regular font = comma or semicolon; green, underlined = coordinating conjunction; blue, italics = dependent clause
Pay close attention to comma usage in complex-compound sentences so that the reader is easily able to follow the intended meaning.
Using some compound-complex sentences in writing allows for more sentence variety.