Syntax is the study of how words are arranged to form meaningful sentences. Mastering sentence structure and punctuation rules is essential for precise communication, standardized testing, and academic writing.

2.1 Sentence Elements

Element	Definition	Example
Subject	Who or what the sentence is about	The committee voted.
Predicate	Everything said about the subject	The students completed the assignment early.
Direct Object	Receives the action of a transitive verb (what? whom?)	She wrote a letter.
Indirect Object	Receives the direct object (to whom? for whom?)	She wrote him a letter.
Object Complement	Renames or describes the direct object	They named her captain.
Subject Complement	Follows a linking verb; renames or describes the subject	She is a scholar.
Appositive	Noun phrase that renames the adjacent noun	My mentor, a retired professor, advised me.

2.2 Clause Types

Type	Definition	Example
Independent (Main)	Expresses a complete thought; can stand alone	She graduated with honors.
Dependent (Subordinate)	Cannot stand alone; introduced by a subordinating conjunction or relative pronoun	because she studied every day
Noun Clause	Functions as a noun (subject, object, complement)	What she said surprised everyone.
Adjective (Relative) Clause	Modifies a noun; introduced by who, whom, whose, which, that	The book that she recommended was outstanding.
Adverb Clause	Modifies a verb, adjective, or adverb; introduced by subordinating conjunction	He left before the meeting ended.

2.3 Sentence Structures

Structure	Definition	Example
Simple	One independent clause	Birds sing.
Compound	Two or more independent clauses joined by a coordinating conjunction or semicolon	Birds sing, and flowers bloom.
Complex	One independent + one or more dependent clauses	Although it rained, the game continued.
Compound-Complex	Two or more independent clauses + at least one dependent clause	Although it rained, the game continued, and the fans cheered.

2.4 Phrase Types

Phrase Type	Function	Example
Noun Phrase	Functions as a noun	The old red barn needs repair.
Verb Phrase	Main verb + auxiliaries	She has been studying all night.
Prepositional Phrase	Preposition + object; acts as adjective or adverb	The book on the shelf is rare.
Participial Phrase	Participle + modifiers; acts as adjective	Exhausted from the race, he collapsed.
Gerund Phrase	Gerund + modifiers; acts as noun	Running a marathon requires months of training.
Infinitive Phrase	Infinitive + modifiers; acts as noun, adj., or adv.	She wanted to finish early.
Absolute Phrase	Noun + participle; modifies entire clause	His work completed, he left the office.

2.5 Sentence Errors to Avoid

Error	Definition	Incorrect	Corrected
Run-on	Two independent clauses joined without proper punctuation	I studied hard I passed the exam.	I studied hard; I passed the exam.
Comma Splice	Two independent clauses joined with only a comma	She was tired, she kept working.	She was tired, yet she kept working.
Fragment	Incomplete sentence lacking a subject or predicate	Running through the park.	She was running through the park.
Dangling Modifier	Modifying phrase has no clear subject to modify	Walking home, the rain started.	Walking home, I got caught in the rain.
Misplaced Modifier	Modifier positioned too far from what it modifies	He almost drove his children to school every day.	He drove his children to school almost every day.
Faulty Parallelism	Items in a series are not grammatically parallel	She likes hiking, to swim, and biking.	She likes hiking, swimming, and biking.

2.6 Punctuation Rules — Quick Reference

Comma

• After introductory elements: After the storm, the sky cleared.
• Before coordinating conjunctions joining independent clauses: She studied, but she was nervous.
• Between items in a series (Oxford/serial comma recommended): red, white, and blue
• Around non-essential (nonrestrictive) clauses: My brother, who lives in Chicago, called me.
• Between coordinate adjectives: a long, difficult journey

Semicolon

• Between independent clauses not joined by a conjunction: The meeting ended; everyone left quickly.
• Before conjunctive adverbs (however, therefore): She was late; however, she was prepared.
• In complex lists whose items contain commas: Paris, France; Rome, Italy; and Athens, Greece.

Colon

• After a complete clause to introduce a list or explanation: She needed three things: patience, skill, and time.
• Before a formal quotation or elaboration: His motto was simple: never quit.
• Do not use a colon after a verb or preposition.

Dash (Em Dash —)

• For strong parenthetical emphasis: The result—after years of effort—was extraordinary.
• Before a summary or amplification: She gave everything she had—her time, her money, her heart.

Apostrophe

• Possession (singular): the student's essay
• Possession (plural ending in s): the students' essays
• Possession (plural not ending in s): the children's books
• Contractions: it's (it is), they're (they are), can't (cannot)
• Never use an apostrophe for possessive pronouns: its, hers, theirs, yours

Quotation Marks

• Commas and periods go inside closing quotation marks (American English).
• Colons and semicolons go outside quotation marks.
• Use single quotes for a quotation within a quotation.

Hyphen vs. En Dash vs. Em Dash

Mark	Use	Example
Hyphen (-)	Compound modifiers before nouns; word division	well-known author, twenty-three
En Dash (–)	Ranges of numbers, dates, scores	pages 10–25, 2001–2010
Em Dash (—)	Parenthetical emphasis, abrupt break	She knew—without a doubt—it was true.