Once you know the parts of speech, the next step is learning how they combine into sentences. Here is everything you need — from the simplest sentence to the most sophisticated.
A sentence is not just a string of words. It is a structure — and once you understand that structure, you can build sentences of any length or complexity with total control.
Every sentence in English, from the shortest command to the longest, most elaborate paragraph opener, is built from the same basic ingredients: subjects, predicates, and the way clauses combine. This guide starts with those basics and works all the way up to the sentence structures used in advanced academic and professional writing.
A complete sentence must do two things: name something (the subject) and say something about it (the predicate). Without both, a group of words is only a fragment, not a sentence.
Birds fly. — "Birds" is the subject, "fly" is the predicate.
The tired old dog slept peacefully on the porch all afternoon. — subject: "The tired old dog." Predicate: everything else.
The subject is who or what the sentence is about. It is usually a noun, pronoun, or noun phrase.
The predicate tells us what the subject does, is, or has done to it. It always contains the main verb.
The exhausted marathon runner (complete subject) collapsed onto the grass and gasped for breath (compound predicate).
This distinction underpins everything that follows, so it is worth getting exactly right.
Clauses come in two kinds, and the difference is the single most important idea in this whole guide.
Expresses a complete thought and can stand alone as its own sentence. Example: "The rain stopped."
Has a subject and verb but cannot stand alone — it depends on an independent clause to complete its meaning. Example: "because the rain stopped" (incomplete on its own).
Every English sentence, no matter how sophisticated, falls into one of exactly four structural categories.
| Structure | Made Of | Example |
|---|---|---|
| Simple | One independent clause | The dog barked. |
| Compound | Two+ independent clauses joined by a coordinating conjunction or semicolon | The dog barked, and the cat ran. |
| Complex | One independent clause + one or more dependent clauses | Because it was raining, the dog barked. |
| Compound-Complex | Two+ independent clauses + one or more dependent clauses | Because it was raining, the dog barked, and the cat ran inside. |
Simple sentences contain a single independent clause — but "simple" does not mean short; a simple sentence can still have a compound subject or predicate, as long as there is only one clause.
Compound sentences link two independent clauses using a coordinating conjunction (remember the acronym FANBOYS: for, and, nor, but, or, yet, so) or a semicolon.
I wanted to go for a walk, but it started raining. / I wanted to go for a walk; it started raining.
Complex sentences combine an independent clause with at least one dependent clause, usually introduced by a subordinating conjunction (although, because, since, when, if, while, unless) or a relative pronoun (who, which, that).
Although she was tired, she finished the race. / The book that I borrowed is overdue.
Compound-complex sentences — the most advanced structure — combine two or more independent clauses with at least one dependent clause, all in a single sentence.
Although the meeting ran late, the team finished the report, and everyone went home satisfied.
Separately from structure, sentences are also classified by what they do:
Standard English follows a Subject–Verb–Object word order, unlike many other languages. Getting this order wrong is one of the most common mistakes for learners moving from another language into English.
Maria (subject) reads (verb) novels (object). Rearranging this order — "Novels reads Maria" — is grammatically incorrect in English.
Even confident writers slip into these three mistakes regularly:
At a more advanced level, strong writing also depends on parallelism — keeping grammatically similar elements in the same form within a sentence, especially in lists.
Incorrect: "She likes reading, to write, and swimming."
Correct: "She likes reading, writing, and swimming."
Relative clauses add detail about a noun using who, whom, whose, which, or that — and come in two forms that change punctuation and meaning.
"The students who studied hard passed the exam." (Only those specific students — essential information.)
"My sister, who lives in Canada, is visiting next month." (Extra detail — the sentence still works without it.)
Consider this sentence from a news report: "Although the storm had passed by morning, residents remained cautious, and local authorities continued monitoring the river levels closely." This is a compound-complex sentence: the dependent clause "Although the storm had passed by morning" sets up the context, while two independent clauses — "residents remained cautious" and "local authorities continued monitoring the river levels" — are joined by "and." Recognising this structure is exactly what separates a fluent reader from someone still decoding word by word.
Sentence structure is the difference between writing that merely communicates and writing that persuades, flows, and holds a reader's attention. Once parts of speech (Topic I) tell you what each word is doing, sentence structure (Topic II) tells you how to arrange those words into clear, correct, and increasingly sophisticated ideas — the exact foundation the rest of this Grammar Basics series builds on.
10 questions. Select an answer for each, then submit to see your score instantly.