Study on the flyACTEnglishRun-ons and comma splices
English
Two complete sentences joined by nothing, or by a comma alone, is the error behind Run-ons and comma splices.
For example, writing "The bus was late, we missed the opening" welds two independent clauses together with only a comma; a period, a semicolon, or a comma plus a word such as and or so repairs it. ACT English underlines the joint between the clauses and asks which version is grammatically acceptable.
The answer options typically swap punctuation marks and connecting words, so several look reasonable at first. Checking whether each side could stand alone as a sentence, and whether the join between them is legal, settles the question.
Pick an answer to see whether it is right — nothing is saved, and nothing needs an account.
When caretakers of old masonry halls need to learn what lies behind a wall, drilling exploratory holes can damage the very surfaces they hope to preserve. Echo tracing offers a gentler approach. In a brick lecture hall scheduled for restoration, the crew works room by room, listening along each plastered wall before any opening is cut. A light wooden striker sends vibrations through plaster and stone. Because solid masonry returns a sharp sound while a hollow chamber produces a softer one, technicians can make an identification of the location of sealed doorways without opening the wall. The survey begins with a chalk grid drawn across the wall. One technician moves the striker methodical from square to square while a second records each change in pitch. A reliable survey requires workers marking the grid, to compare nearby sounds, and estimating each hollow area’s size. When a doubtful patch needs review, site supervisor Lena Ortiz joins mason Carlos Ruiz, and Carlos and she repeat the sequence.
Consistency matters more than force. Every striker is returned to their labeled slot, since differences in weight can alter the sound. Technicians also reject any striker who’s handle is loose. Each echo appears as a shaded cell on the map, the team1 adds notes about nearby windows and beams. These notes help distinguish an actual chamber from ordinary variations in the wall’s construction. A dark band beside a window may look like a sealed doorway until the notes show that the shading simply follows a timber that has always belonged to the frame.
An isolated dark cell does not prove a cavity several neighboring cells must2 form a coherent outline before the team recommends closer inspection. Even then, the map is a guide rather than a verdict. Behind similar dull responses, there is often several explanations: an empty flue, a timber brace, or a deliberately filled doorway. Only careful comparison with the visible structure allows the crew to interpret what the wall seems to say.
Question 1Easier
Which choice makes the sentence most grammatically acceptable?
Answer: D — map; the team
The clauses on both sides of the marked portion can stand alone as sentences, so a semicolon can join them. A comma alone creates a comma splice.
Question 2Easier
Which choice makes the sentence most grammatically acceptable?
Answer: B — cavity. Several neighboring cells must
The original joins two independent clauses without punctuation, creating a fused sentence. A period after “cavity” correctly separates the clauses into complete sentences. The comma choice incorrectly sets off the subject, and the semicolon with “but” adds an illogical contrast.
Every question is picked for where you are right now, wrong answers come back until they stick, and it all works offline.
Study on the fly is an independent study tool and is not affiliated with, sponsored by, or endorsed by any testing organization, school, or government body.
ACT® is a registered trademark of ACT Education Corp., which is not affiliated with, and does not endorse, this product.
All practice questions and passages are original works created for Study on the fly and are not reproduced from any official test.