Correcting Punctuation Errors: Commas - SAT Writing

Commas can only be used between dependent and independent clauses. When a comma splits two independent clauses, as in this question, it becomes a "comma splice", and is gramatically incorrect. Either a period or semi-colon should be used.

This sentence is a run-on, and should be split into two sentences with the appropriate punctuation, or given a proper conjunction.

The sentence as presented is actually two complete thoughts united in one sentence, which is done to contrast the two thoughts. In these instances, the thoughts should be broken up more concretely than by one comma. The correct answer choice utilizes a semi-colon to unite the two sentences in one.

The two phrases in the sentence have slightly contradictory ideas, with the second one modifying the first. A conjunction is needed to show these differences in the two phrases. The correct answer is the one that uses "but" to separate the two parts.

The sentence is composed of two independent clauses—two complete sentences, joined to show their connection; however, the two are joined only by a comma, creating an error known as a "comma splice." Independent clauses should be joined by a semi-colon or by a comma followed by a conjunction (a word like "and" or "but"). To correct this sentence, you could either change out the comma for a semi-colon, or insert an appropriate conjunction immediately after the comma.

Let's consider the possible answer choices. The answer choice that makes no changes to the sentence can't be correct, since the sentence does contain an error. "Also" is an adverb, not a conjunction, so the answer choice that uses it as a conjunction cannot be correct. The remaining answer choices properly use "but," "so," and "although" as conjunctions, so finding the right answer becomes a matter of picking the conjunction that matches the logic of the sentence. "But" and "although" are used to indicate that the second sentence contrasts in some way with the first; this wouldn't make sense in our sentences, since they don't contrast with each other, but are related by causation: the first sentence explains the second. "So" is thus the proper conjunction to use, making the correct answer, "She was quite wary of making a scene, so she let the matter fade away with no comment."

The sentence actually contains two complete sentences, which are placed together to show their thematic ties. Any such complex sentence must be joined either by a comma and conjunction or a semi-colon. The only answer choice containing such a construction is "bosses; many relied."

The best answer fixes the comma splice, uses a more logical coordinator (“although”), and is more concise.

Two dependent clauses cannot be separated with a comma: here a semi-colon or period would be appropriate. Between answers with proper puncutation, choose the simplest one which keeps the meaning of the original sentence.

Two complete phrases should not be separated by a comma: instead a semi-colon, colon, or period should be used. Choose the answer which separates the phrases and otherwise makes grammatical sense.

The sentence is a compound sentence, two complete thoughts that are joined in one sentence. All compound sentences need to have their two parts joined by either a semicolon or a comma and a conjunction; therefore, the correct answer is "Everyone was aware of the man's financial troubles, few knew just how deep in debt he truly was."

Each of the clauses being combined in the sentence, "Jeff couldn't stand his precalculus teacher" and "she would always demean him in front of his peers" could function on its own as a complete sentence. This means that each clause is an independent clause, and because of this, the two should not be linked by just a comma; doing this creates an error called a "comma splice."

Without adding any words, you could merge the two clauses using a period or a semicolon; alternatively, you could add in an appropriate conjunction immediately after the comma. "As" works as just such a conjunction here, since Jeff's dislike for his teacher is because of her demeaning treatment of him. "Though" will not work, because it would suggest that he disliked her in spite of her negative treatment of him. So, the correct answer is "as she would always demean him in front of his peers," making the complete corrected sentence, "Jeff couldn't stand his precalculus teacher, as she would always demean him in front of his peers."

A colon is the most appropriate punctuation to use when combining the two independent clauses present in the sentence because the second clause clarifies or elaborates the first clause. So, the correct answer is "As their spaceship landed, the aliens began emitting a screeching message regarding their intent: they desired to make peace with the humans."

The sentence is a compound sentence, or two related complete sentences that are put together in one sentence to show their relationship. To be grammatically correct, the two parts must be joined either by semicolon or a comma and a conjunction. The only answer choice to do either is "The coins thrown in the fountain would pile up at the end of the day; an employee had to clear them out after closing time."

The sentence is a complex sentence, featuring two complete thoughts put together to form one sentence. To appropriately join the two thoughts, they need to have a semicolon or a comma and a conjunction. "The cold weather can be quite difficult for young children, so companies offer special clothing for infants during the winter months," is the only correct answer.

The sentence is compound, meaning it is composed of two complete sentences joined together for effect. Compound sentences, though, must be joined by either a semicolon or a comma and a conjunction. Using "as" for its conjunction, "to be taken lightly, as many people" is the correct answer choice.

This sentence is a compound sentence, a sentence that joins two complete thoughts to demonstrate their relationship. All compound sentences must be joined together either by a semicolon or a comma and a conjunction. Of the answer choice, only "in terrible shape, and none of them" appropriately joins the two parts.

The second part of the sentence is a dependent clause, one that cannot stand alone as its own complete sentence; therefore, it needs to be appropriately connected to the first portion of the sentence with the correct preposition. Of all the answer choices, only "hotly debated, after new information" does this.

The sentence is a compound sentence, featuring two complete, but intimately related, thoughts as one sentence. To properly connect the two parts, either a semicolon or a comma and a conjunction need to be used between the sections. Therefore, the correct answer is "The exterminator bragged about his new method for controlling rats; the method improved on its precedents by being done more quickly."

The sentence is written as a compound sentence, but instead of having its two parts appropriately linked, the sentence has a comma splice in the middle of its two components. All compound sentences must be linked either by a semicolon or by a comma and a conjunction. So, the correct answer is "The fugitive famously slipped away in the middle of the night; he was never seen again."

The sentence written above is a compound sentence, a sentence formed by two complete thoughts that are joined to show their relationship. The appropriate ways to join complete sentences is either with a semi-colon or a comma and a conjunction. The only answer choice that does this is "The politicians grew more and more nervous about the legislation passing with each day; former supporters were switching sides with regularity."