Difficulty: Beginner | Prerequisites: None
Every English sentence is built from a small set of moving parts: subjects, verbs, objects, prepositions and clauses. This material sits at the foundation of the entire ENG 101 course. If you can label these parts reliably, every later grammar topic (modifiers, agreement, voice, fragments) becomes far easier to diagnose. You do not need any prior grammar knowledge to start here.
Subjects do the action, verbs are the action, objects receive it. Prepositional phrases add detail about where, when or how. Independent clauses can stand alone as sentences; dependent clauses cannot, and the way you join them determines whether you have a correct sentence, a run-on or a fragment.
Subject (S)
The noun or pronoun performing the action in a sentence. In simple terms, the subject is whoever or whatever the sentence is about.
Verb (V)
The word (or words) expressing the action or state of being. Think of it as what the subject does or is.
Object (O)
The noun or pronoun receiving the action of the verb. In simple terms, the object is the thing being acted upon.
Preposition
A word that shows the relationship between a noun (or pronoun) and another element in the sentence, typically indicating location, time or direction. Common examples: in, on, at, before, between, for, by, near, with.
Prepositional phrase
A group of words beginning with a preposition and ending with its object (the noun or pronoun the preposition connects to the rest of the sentence). Think of it as a small package of extra detail: "in the morning," "between the buildings."
Independent clause
A group of words containing a subject and a verb that expresses a complete thought and can stand on its own as a sentence. In simple terms, it works as a sentence by itself.
Dependent clause (subordinate clause)
A group of words containing a subject and a verb that does not express a complete thought. It relies on an independent clause to make sense. Typically introduced by a subordinating conjunction (because, since, although, if, when) or a relative pronoun (who, which, that).
The basic drill is to read a sentence and mark each word's role:
S = the doer (or the thing described)
V = the action or linking verb
O = whoever or whatever receives the action
Worked examples from the quiz prep:
"Kim (S) ate (V) Kanye's dinner (O)." A straightforward subject-verb-object sentence.
"Bernie Sanders (S) knows (V) Hillary's personal phone number (O)." The object is the entire noun phrase, not just "number."
"Rand Paul (S) is (V) angry." Here "angry" is a predicate adjective, not an object. The dependent clause "because no one voted for him" adds a reason but contains its own S-V structure: "no one (S) voted (V)."
"Santa Claus (S) is making (V) toys (O)." The verb is a two-word phrase (auxiliary + main verb).
"Gary and his brother (S) fly (V) airplanes (O)." A compound subject joined by "and" still counts as one subject unit.
Key pattern to watch: compound subjects (two nouns joined by "and") and multi-word verbs (is making, will be, have been). Students lose marks by labelling only part of the subject or part of the verb.
A prepositional phrase = preposition + its object (plus any modifiers of that object). On the quiz you will be asked to bracket the entire phrase, underline the preposition and circle the object noun.
How to find them: scan the sentence for prepositions (before, in, by, near, between, for, with, to, of, at, on) and then read forward until you hit the noun that completes the phrase.
Worked examples:
"[Before the game] we went [to the concession stand] [between the high school and the gym]." Three prepositional phrases. Notice that "between" takes a compound object ("the high school and the gym").
"[In the morning] I never feel like doing anything [for school]." Two phrases. "Like doing anything" is not a prepositional phrase because "like" here functions as part of the verb "feel like."
"[By the time he arrives] we will already be [in the movie theatre]." "By the time he arrives" is a prepositional phrase where the object of "by" is "the time."
"[Near my house] there is a field where people [with little money] wait [for work]." Three phrases. "Where" introduces a clause, not a prepositional phrase.
"We can't distinguish [between candidates who work [for the people] and those who work [for themselves]]." Nested prepositional phrases: "for the people" and "for themselves" sit inside the larger "between" phrase.
Tip: one prepositional phrase can contain another. Read carefully and bracket from the inside out if you are unsure.
An independent clause has a subject + verb and expresses a complete thought. A dependent clause has a subject + verb but cannot stand alone because it begins with a subordinating word (since, because, although, if, when, after, while, however).
Punctuation rules for joining clauses:
Dependent clause first, then independent: place a comma after the dependent clause. "Since you've been gone, I can't think straight."
Independent clause first, then dependent: usually no comma needed. "I can't think straight since you've been gone."
Two independent clauses: join with a comma + coordinating conjunction (for, and, nor, but, or, yet, so), or with a semicolon. "I didn't read the entire book, but it didn't affect me on the quiz."
Two independent clauses with a conjunctive adverb (however, therefore, moreover): use a semicolon before the adverb and a comma after it. "The student came to class; however, he forgot his book."
Worked examples:
"Since you've been gone, I can't think straight." Dependent clause: "Since you've been gone." Independent clause: "I can't think straight." Comma after the dependent clause.
"I like pizza; I prefer pepperoni." Two independent clauses. As written without punctuation, this is a run-on. Fix: semicolon, or a comma + "but."
"The student came to class; however, he forgot his book." "However" is a conjunctive adverb, not a coordinating conjunction, so it needs a semicolon before it and a comma after.
"We decided to go to Taco Cabana after the Two Chains show." Independent clause: "We decided to go to Taco Cabana." Dependent clause: "after the Two Chains show." No comma needed because the independent clause comes first.
"I didn't read the entire book, but it didn't affect me on the quiz." Two independent clauses joined by the coordinating conjunction "but" with a comma before it.
Students often think the object of a preposition and the direct object of the verb are the same thing. They are not. In "She walked to the store," "store" is the object of the preposition "to," not the direct object of "walked."
Students frequently label only the main verb and miss the auxiliary. In "is making," the full verb is "is making," not just "making."
"However" is commonly mistaken for a coordinating conjunction (like "but"). It is a conjunctive adverb and requires a semicolon before it when joining two independent clauses, not just a comma.
Students sometimes assume that any clause starting with a capital letter and ending with a full stop is an independent clause. A fragment such as "Because this is important." has a subject and verb but is still a dependent clause because "because" makes it subordinate.
⚠️ The quiz format is: you see a sentence with a mistake, label the type of mistake, and correct it. Practise identifying the error type before jumping to the fix.
⚠️ Expect sentences where two independent clauses are jammed together without punctuation (run-ons) or joined only by a comma (comma splices). Know the three correct fixes: semicolon, comma + coordinating conjunction, or full stop.
⚠️ "However" punctuation is a near-certain test item. Semicolon before, comma after.
⚠️ Compound subjects ("Gary and his brother") and multi-word verbs ("is making," "will already be") appear in labelling questions. Mark the entire unit.
True or False: "Because I was tired" is an independent clause. (False: "because" makes it dependent.)
True or False: In "The dog chased the ball," "ball" is the object of a preposition. (False: it is the direct object of "chased.")
Fill in the blank: To correctly join two independent clauses with "however," place a ______ before it and a ______ after it. (Semicolon; comma.)
True or False: "Gary and his brother" counts as a compound subject. (True.)
Fill in the blank: A prepositional phrase always begins with a ______ and ends with its ______. (Preposition; object.)
Q: Identify the subject, verb and object in: "The committee reviewed the proposal."
A: Subject = "The committee." Verb = "reviewed." Object = "the proposal."
Q: List all prepositional phrases in: "After the meeting, she drove to the office near the river."
A: "After the meeting," "to the office," "near the river."
Q: Is the following a run-on, a comma splice, or correct? "I like pizza I prefer pepperoni."
A: Run-on. Two independent clauses with no punctuation between them. Fix: "I like pizza; I prefer pepperoni" or "I like pizza, but I prefer pepperoni."
Q: Punctuate correctly: "The student came to class however he forgot his book."
A: "The student came to class; however, he forgot his book." Semicolon before "however," comma after.
Q: In the sentence "Before the game, we went to the stand between the school and the gym," how many prepositional phrases are there?
A: Three: "Before the game," "to the stand," "between the school and the gym."
This connects directly to fragments and run-ons: once you can tell an independent clause from a dependent one, diagnosing fragments (dependent clause standing alone) and run-ons (two independent clauses improperly joined) becomes mechanical.
It also connects to subject-verb agreement: you need to identify the true subject before you can check whether the verb matches it in number.
Understanding prepositional phrases helps with misplaced modifiers, because modifiers often take the form of prepositional phrases and need to sit next to what they describe.
Related Terms / Search Tags
subject verb object, SVO, sentence parts, prepositional phrase, preposition object, independent clause, dependent clause, subordinate clause, coordinating conjunction, subordinating conjunction, conjunctive adverb, FANBOYS, comma splice, run-on sentence, clause punctuation, ENG 101 grammar, sentence diagramming, compound subject, multi-word verb, auxiliary verb