Praxis Core Sentence Correction and Mechanics Summary

"The students finished the experiment" and "they wrote their reports" are both complete sentences. Joining them with only a comma creates a comma splice. A semicolon correctly joins them.

Wrong choices

• ", they wrote": This is a comma splice: two complete sentences joined only by a comma.
• " they wrote": This is a run-on sentence: two complete sentences with no punctuation between them.
• ", and writing": "Writing" breaks the sentence structure and leaves the second part incomplete.
• ", while they wrote": "While" means the actions happened at the same time, but the reports were written the next day.

"Because her students needed extra help with fractions" is a fragment; it cannot stand alone. Attaching it to the first sentence without a period makes one complete sentence.

Wrong choices

• ". Because her students": This leaves a fragment that begins with "Because."
• ". Her students, because they": "Her students, because they needed extra help with fractions" has no main verb, so it is still a fragment.
• "; because her students": A semicolon must join two complete sentences, and the "because" part is not complete.
• ", her students": This creates a comma splice, joining two complete sentences with only a comma.

The list already has "hiking" and "swimming," which end in -ing. The third item should match: "riding her bike."

Wrong choices

• "to ride her bike": "To ride" does not match the -ing words in the list.
• "she rides her bike": "She rides her bike" is a full clause, not matching the other items.
• "to go bike riding": "To go" still breaks the -ing pattern.
• "a bike ride": "A bike ride" is a noun phrase, not matching "hiking" and "swimming."

The schedule belongs to the school, so the possessive "its" (no apostrophe) is correct. "It's" always means "it is" or "it has."

Wrong choices

• "it's lunch schedule": "It's" means "it is," which makes no sense here.
• "its' lunch schedule": "Its'" is not a real word in English.
• "it is lunch schedule": "It is lunch schedule" makes no sense in this sentence.
• "their's lunch schedule": "Their's" is not a real word, and "school" is singular.

In the original, "Walking to school" seems to describe the rain, which cannot walk. The best version names Jamal as the one walking.

Wrong choices

• "Walking to school, the rain soaked Jamal's backpack.": This says the rain was walking to school (a dangling modifier).
• "Walking to school, Jamal's backpack was soaked by the rain.": This says the backpack was walking to school.
• "Walking to school, the rain was soaking Jamal's backpack.": This still says the rain was walking to school.
• "Walking to school, rain soaked the backpack of Jamal.": This still says the rain was walking, and "the backpack of Jamal" is awkward.

"Which opened in 1920" is extra information about the library, so it needs a comma before and after it. The original is correct.

Wrong choices

• "which opened in 1920 is": This drops the second comma, so the extra information is not closed off.
• "that opened in 1920, is": "That" is used for necessary information, which is not set off with commas.
• "which opened in 1920, it is": "It" repeats the subject "library" and is not needed.
• "opening in 1920, was being": "Was being" is the wrong tense for a building that is still the oldest.

"However" is not a joining word like "but." When it links two complete sentences, put a semicolon before it and a comma after it.

Wrong choices

• ", however, most students": Commas alone around "however" create a comma splice.
• " however most students": With no punctuation, the two sentences run together.
• ", however most students": This is still a comma splice, just missing the second comma.
• ", but however, most students": "But however" says the same thing twice.

"Due to the fact that" is a wordy way to say "because." "Because the bus was late, the students" says the same thing clearly and correctly.

Wrong choices

• "Due to the fact that the bus was late, the students": It is not wrong, but it is wordy compared with "because."
• "Due to the bus being late the students": It is awkward and is missing the comma after the opening phrase.
• "Because the bus was late the students they": "The students they" repeats the subject.
• "The bus being late, and so the students": "And so" leaves the sentence without a proper structure.

"Who attended the workshop" tells which teachers, so it needs no commas. A comma should not separate the subject ("teachers") from its verb ("said").

Wrong choices

• "The teachers who attended the workshop, said": The comma wrongly separates the subject from the verb.
• "The teachers, who attended the workshop said": It has only one comma, so the inserted words are not properly set off.
• "The teachers who attended the workshop, they said": "They" repeats the subject.
• "The teachers who attended, the workshop said": The comma makes it seem the workshop said something.

In the original, "she" could mean Ms. Diaz or Ms. Cole. Naming Ms. Diaz removes the confusion.

Wrong choices

• "she explained the new grading policy": "She" could refer to either woman.
• "she explained to her the new grading policy": Both "she" and "her" are still unclear.
• "they explained the new grading policy to her": "They" cannot explain something "to her" when both women are meeting.
• "the new grading policy was explained by her": "By her" is still unclear and the passive voice is wordy.