Combining Sentences Check In, Subjects, Verbs and Adjectives
Written by Adi Ackerman, Head Teacher
"Combining Sentences Check In, Subjects, Verbs and Adjectives" is written for 3rd Grade (Ages 8-9), and it covers Common Core L.3.1.I. If your little one is a year younger but already steady on sentence structure, the page still works. You may just need to read the instructions out loud. And if they are older and combining sentences never quite stuck, this is a short review rather than busywork.


3rd grade grammar worksheet: check in on combining sentences by joining actions, joining subjects and moving an adjective. Answer key included. Part of our combining sentences sentence structure collection. Aligned to Common Core standards.
How do I use this worksheet?
Have your child read both sentences aloud and say which words repeat. Cross out the repeated part, then read the new sentence to hear that it still means the same thing. Check with the answer key.
What students will practice
- Students will combine two sentences that share a subject or an action into one sentence.
- Students will join two sentences with a comma and the conjunction and, but or or.
- Students will move an adjective in front of its noun to combine two sentences.
Curriculum Links
Common Core State Standards
Language · 3rd Grade
Standard: Produce simple, compound, and complex sentences.
View all L.3.1.I worksheets →Find this in the curriculum
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FAQ
How do I use this combining sentences worksheet?
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Have your child read both sentences aloud and say which words repeat. Cross out the repeated part, then read the new sentence to hear that it still means the same thing. Check with the answer key.
What does this worksheet teach?
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Check in on combining sentences by joining actions, joining subjects and moving an adjective. To combine is to join two sentences. An adjective describes a noun. The directions on the page read: In Part A, join the actions with and. In Part B, join the subjects with and. In Part C, move the adjective before the noun. An answer key is included.
Can I use this combining sentences worksheet for homeschool or classroom?
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Yes, both. We made it for 3rd Grade sentence structure, and the page works the same whether it lands on a kitchen table or a center rotation. At home, most families go through it together and talk the answers out loud, and that talking is where most of the learning happens with combining sentences. In class it runs well as independent work while you pull a small group. Print one copy or thirty, whichever the day needs.
What does it mean to combine sentences?
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Combining means joining two short sentences into one so the shared part is said only once. Mia ran. Mia jumped. becomes Mia ran and jumped.
What is a compound subject?
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A compound subject is two subjects joined by and that share one action, like The cat and the dog slept. When one of the subjects is I, it goes last, as in My aunt and I sang.
When does a combined sentence need a comma?
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When two complete sentences are joined with and, but or or, a comma goes before the joining word, as in It rained, but we played. Joining only two actions, like hopped and skipped, needs no comma.
Is there an answer key for each worksheet?
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The five newer combining sentences sheets each have an answer key. The key also accepts the two parts in the other order, as long as the sentence keeps its meaning.
What sentence structure skills should third graders develop?
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Third graders should produce simple, compound, and complex sentences, as specified in CCSS L.3.1i. Simple sentences have one independent clause (The dog barked). Compound sentences join two independent clauses with a coordinating conjunction (The dog barked, and the cat ran). Complex sentences combine an independent clause with a dependent clause using a subordinating conjunction (When the dog barked, the cat ran). Students should understand how to vary their sentence structure to create more engaging writing. They should also master subject-verb agreement in these longer structures and maintain consistent verb tense throughout a piece. Worksheets that ask students to identify sentence types, combine simple sentences into compound or complex sentences, and expand sentences with phrases and clauses provide comprehensive structure practice. Third grade represents a significant leap in sentence sophistication, moving from the two-clause compound sentences of second grade to the multi-clause complexity that defines mature writing.
How do I help my third grader write complex sentences?
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Start by teaching subordinating conjunctions as the key that unlocks complex sentences. Common third grade subordinating conjunctions include because, when, if, although, since, while, before, after, and until. Show how these words create a dependent clause that cannot stand alone: "Because it rained" is not a complete thought, but "Because it rained, we stayed inside" is a complex sentence. Practice the two patterns: conjunction at the beginning (comma needed: "When the bell rings, we line up") and conjunction in the middle (no comma needed: "We line up when the bell rings"). Worksheets that give students two related sentences and a subordinating conjunction, asking them to combine them, build this skill step by step. Sentence imitation exercises where students follow the pattern of a model complex sentence with their own content develop structural awareness. Encourage your child to use at least one complex sentence per paragraph in their writing. CCSS L.3.1i makes complex sentences a priority skill because they enable students to express relationships between ideas.
What is the difference between compound and complex sentences for third graders?
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A compound sentence joins two independent clauses (each could be a sentence on its own) with a coordinating conjunction: "I like math, and my sister likes reading." Both parts are equal in importance. A complex sentence joins an independent clause with a dependent clause (one that cannot stand alone as a sentence) using a subordinating conjunction: "I like math because it involves puzzles." The dependent clause ("because it involves puzzles") needs the independent clause to be complete. The simplest test for third graders: cover each part separately. If both parts can stand alone as sentences, it is compound. If one part cannot stand alone, it is complex. Use color coding on worksheets: underline independent clauses in one color and dependent clauses in another. Circle the conjunction and identify whether it is coordinating (compound) or subordinating (complex). This visual approach makes the abstract distinction concrete. CCSS L.3.1i expects students to produce both types, so worksheets that require students to write examples of each and label them correctly build both understanding and production skills.
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Worksheet Details
| Grade | 3rd Grade |
| Subject | Grammar & Writing |
| Topic | Sentence Structure |
| Standard | L.3.1.I |
| Pages | 1 page |
| Difficulty | Medium |
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