Sentence boundaries and combining on the Grade 10 ELA MCAS: fixing fragments, comma splices, and run-ons by recognizing independent and dependent clauses, and combining short, choppy sentences using coordination, subordination, and other joins to improve flow and variety, in editing and revising items and the long composition.

What this skill is asking

Sentence boundaries and sentence combining are two sides of one skill: knowing where sentences should begin and end, and joining clauses well. The Grade 10 ELA MCAS tests fixing boundary errors, fragments, comma splices, and run-ons, in editing items, and combining short, choppy sentences for flow and variety in revising items. Both rest on recognizing independent clauses (complete thoughts) and dependent clauses (incomplete ones). The skill students lose ground on is misjudging where a sentence ends (leaving a splice or run-on) or combining sentences in a way that creates a new error or changes the meaning. This page covers fixing the three boundary errors and combining sentences with coordination and subordination. The transferable skill is controlling sentence structure, which fixes editing items, improves revising items, and supports both the conventions and the readability of the long composition.

Fixing the three boundary errors

The first move is to recognize clauses so the errors become visible.

Because all three errors come from the same root, misjudging where a complete thought ends, the cure is the same diagnosis: find the independent clauses and check how they are joined. A fragment is missing an independent clause; a splice and a run-on have two joined incorrectly. The four fixes give you options, and the best one often depends on the relationship between the ideas: subordination is ideal when one idea depends on the other ("When the rain stopped, we went outside"), while a period or semicolon suits two equally weighted ideas.

Combining sentences for flow

Combining and boundary-fixing are the practical payoff of understanding clauses: one removes errors, the other builds better sentences. A passage of short, repetitive sentences ("The dog was small. The dog was fierce. It guarded the yard.") is choppy, and the revising move is to combine them smoothly while keeping every idea. The trap is over-combining into a run-on or splice, so the combined sentence must still be correctly bounded. This sentence control connects to varied sentence style in author's craft on the reading side, and it directly serves your own writing, where sentence variety makes the essay clearer and more fluent.

Working a boundary or combining item

Try this

Q1. Name the three sentence-boundary errors and one fix that works for a run-on. [Recall]

• Cue. Fragment, comma splice, and run-on. A run-on can be fixed with a period, a semicolon, a comma plus a coordinating conjunction, or by subordinating one clause ("When the rain stopped, we went outside").

Q2. Combine for flow without error: "The lake was calm. The lake was clear. We swam all afternoon." [Short explanation]

• Cue. Something like: "The calm, clear lake was perfect for swimming, so we swam all afternoon," or "Because the lake was calm and clear, we swam all afternoon." Each merges the ideas smoothly, keeps the meaning, and stays correctly bounded.