4.2 Sentence Structure & Idioms

Sentence Structure & Idioms

Mastering sentence structure is crucial for the DCAT, as it allows you to communicate complex ideas clearly and logically. This section of the exam evaluates your ability to identify and correct structural flaws in sentences, such as run-ons, fragments, faulty parallelism, and misplaced modifiers. Additionally, you will be tested on your knowledge of English idioms and your ability to complete sentences logically using appropriate vocabulary and structural cues. A sentence that "sounds good" is not necessarily structurally sound; you must apply rigorous grammatical rules to arrive at the correct answer.

Sentence Boundaries: Fragments and Run-ons

The foundation of a grammatically correct sentence is the independent clause, which must contain at least one subject and one working verb, and must express a complete thought. Errors in sentence boundaries occur when these rules are violated.

Sentence Fragments

A sentence fragment is an incomplete sentence masquerading as a complete one. Fragments typically lack a subject, a verb, or fail to express a complete thought because they begin with a subordinating conjunction (like although, because, since, if).

Incorrect: Because the weather was unexpectedly severe. (This is a dependent clause and cannot stand alone). Correct: Because the weather was unexpectedly severe, the outdoor concert was canceled.

Run-on Sentences and Comma Splices

A run-on sentence occurs when two independent clauses are improperly joined. The most common variation of a run-on tested on the DCAT is the comma splice, where two independent clauses are joined by only a comma.

Incorrect (Comma Splice): The experiment yielded surprising results, the team decided to publish the data immediately.

You can fix a comma splice or run-on in several ways:

1. Use a period: ...results. The team...
2. Use a semicolon: ...results; the team...
3. Use a comma and a coordinating conjunction (FANBOYS): ...results, so the team...
4. Make one clause dependent: Because the experiment yielded surprising results, the team...

Trap Alert: A conjunctive adverb like however, therefore, or nevertheless cannot link two independent clauses with just a comma. You must use a semicolon before the conjunctive adverb (e.g., ...results; however, the team...).

Coordination and Subordination

Coordination gives equal grammatical weight to two or more independent clauses. This is achieved using coordinating conjunctions, which can be memorized using the acronym FANBOYS: For, And, Nor, But, Or, Yet, So.

Subordination, on the other hand, gives unequal weight to clauses, making one dependent on the other. Subordinating conjunctions (e.g., although, whereas, while, because, since) establish a specific logical relationship between the clauses, such as cause-and-effect or contrast. Choosing the correct conjunction based on the logic of the sentence is heavily tested. If a sentence presents a contrast, "although" or "but" is appropriate; if it presents a cause, "because" or "since" should be used.

Parallel Structure

Parallelism, or parallel structure, dictates that items in a series, list, or comparison must be in the same grammatical form. This creates balance and readability in writing. If you start a list with a gerund (an -ing verb), all subsequent items must also be gerunds.

Incorrect: The new manager prioritized organizing the files, updating the software, and to train the new employees. Correct: The new manager prioritized organizing the files, updating the software, and training the new employees.

Parallelism is also required when using paired conjunctions, known as correlative conjunctions:

• Either X or Y
• Neither X nor Y
• Not only X but also Y
• Both X and Y

The grammatical structure that immediately follows the first part of the pair must exactly match the structure following the second part. Incorrect: She was not only frustrated by the delays but also by the poor communication. Correct: She was frustrated not only by the delays but also by the poor communication.

Modifiers: Misplaced and Dangling

A modifier is a word, phrase, or clause that describes or provides more information about another part of the sentence. The golden rule of modifiers is that they must be placed as closely as possible to the noun or pronoun they modify.

Misplaced Modifiers

A misplaced modifier is positioned too far from the word it modifies, resulting in a sentence that is confusing or unintentionally humorous. Incorrect: The waiter served a steak to the customer that was burned. (Was the customer burned, or the steak?) Correct: The waiter served a burned steak to the customer.

Dangling Modifiers

A dangling modifier occurs when the noun or pronoun being modified is entirely missing from the sentence. These usually appear at the very beginning of a sentence as an introductory phrase. Incorrect: Walking through the dense forest, the ancient ruins were finally discovered. (The ruins were not walking through the forest). Correct: Walking through the dense forest, the explorers finally discovered the ancient ruins. (The subject "explorers" must immediately follow the introductory modifying phrase).

Sentence Completion and Idioms

Sentence completion questions require you to fill in one or two blanks with the most appropriate vocabulary words or phrases. Success in this section relies heavily on identifying structural clues within the sentence. Look for "road sign" words that indicate the direction of the sentence's logic:

• Continuation/Support: and, moreover, similarly, consequently, thus.
• Contrast/Opposition: but, however, although, paradoxically, conversely, despite.

Additionally, the DCAT frequently tests your knowledge of common English idioms. An idiom is a phrase whose figurative meaning differs from the literal meaning of its individual words. Examples include:

• By and large: Generally speaking.
• A blessing in disguise: A good thing that initially seemed bad.
• Bite the bullet: To endure a painful or difficult situation.
• On the fence: Undecided or hesitant.

Mastering sentence boundaries, parallel structure, modifier placement, and common idioms will allow you to quickly eliminate grammatically flawed answer choices and significantly improve your accuracy on the Sentence Structure and Idioms section of the exam.