ACT English: Punctuation (Drill 4)

Question 1. Which choice makes the sentence most grammatically acceptable?

• A) No Change (something no one had thought possible — a complete map of the ocean floor.) ✓
• B) something no one had thought possible, a complete map of the ocean floor.
• C) something no one had thought possible: a complete map of the ocean floor.
• D) something no one had thought possible; a complete map of the ocean floor, as punctuated in the sentence.

Explanation: Choice A (No Change) is correct. A dash is the ideal punctuation here — it introduces "a complete map of the ocean floor" with dramatic emphasis after the buildup of "something no one had thought possible." The dash signals a reveal, which perfectly matches the sentence's tone. Choice B uses a comma, which is too mild for this dramatic moment; a comma simply apposes the phrase without conveying the sense of revelation. Choice C uses a colon, which is also technically defensible — a colon can introduce a clarifying explanation. However, "a complete map of the ocean floor" follows "something no one had thought possible," which is not a complete independent clause, so a colon is less appropriate than a dash here. Choice D uses a semicolon, which must join two independent clauses; "a complete map of the ocean floor" is a noun phrase, not a clause.

Question 2. Which choice makes the sentence most grammatically acceptable?

• A) No Change (which had been praised by engineers across the country, reduced) ✓
• B) which had been praised by engineers across the country reduced
• C) which had been praised, by engineers across the country, reduced, as punctuated in the sentence
• D) which had been praised by engineers across the country; reduced

Explanation: Choice A (No Change) is correct. "Which had been praised by engineers across the country" is a nonrestrictive relative clause — it adds information about the bridge design but is not essential to identify which design is meant. The sentence opens with "The new bridge design," followed by a comma, so the nonrestrictive clause must be closed with a comma after "country" before the main verb "reduced." Choice B omits the closing comma, running the clause into the main verb. Choice C incorrectly breaks the clause mid-thought by placing commas around "by engineers across the country," treating that phrase as a separate nonrestrictive element when it is simply part of the "which" clause. Choice D uses a semicolon after "country," which would make "reduced construction costs by nearly a third" an independent clause missing a subject.

Question 3. Which choice makes the sentence most grammatically acceptable?

• A) No Change (droughts, this one, however, proved)
• B) droughts, this one however proved
• C) droughts; this one, however, proved ✓
• D) droughts: this one, however, proved

Explanation: Choice C is correct. The sentence joins two independent clauses — "The colony had survived three consecutive droughts" and "this one, however, proved too severe to overcome" — with the conjunctive adverb "however." A semicolon must precede "this one," and "however" must be set off by commas on both sides. Choice A creates a comma splice; a comma alone cannot join two independent clauses even with a conjunctive adverb. Choice B omits the commas around "however," and the comma before "this one" is still a splice. Choice D uses a colon, which would imply the second clause directly explains or enumerates the first — but the relationship here is contrast, not elaboration, making a semicolon the better choice.

Question 4. Which choice makes the sentence most grammatically acceptable?

• A) No Change (debated, whether)
• B) debated; whether
• C) debated whether ✓
• D) debated — whether

Explanation: Choice C is correct. "Whether to restore the original clock mechanism or replace it entirely" is a noun clause acting as the direct object of "debated." No punctuation should separate a verb from its direct object. "Debated whether" is clean and correct. Choice A inserts a comma between "debated" and "whether," incorrectly separating the verb from its direct object clause. Choice B uses a semicolon, which must be followed by an independent clause — "whether to restore..." is a noun clause, not an independent clause. Choice D uses an em dash, which signals a dramatic pause or interruption; there is no such pause needed here between a verb and its object.

Question 5. Which choice makes the sentence most grammatically acceptable?

• A) No Change (exhaustion the expedition leader)
• B) exhaustion, the expedition leader ✓
• C) exhaustion; the expedition leader
• D) exhaustion, the expedition, leader

Explanation: Choice B is correct. "When the last of the sled dogs collapsed from exhaustion" is an introductory adverbial clause. A comma must follow an introductory clause to separate it from the main clause. "Exhaustion, the expedition leader" correctly places that comma. Choice A omits the comma, running the subordinate clause directly into the main clause. Choice C uses a semicolon, which can only join two independent clauses — the introductory "when" clause is dependent and cannot stand alone. Choice D inserts a comma after "expedition," incorrectly splitting the subject "the expedition leader."