1. Clauses and Phrases
A clause is a group of related words that has both a subject and a predicate.
A phrase is a group of related words that function as a single part of speech. A phrase is missing a subject, a predicate, or both.

2. Clauses
An independent clause (IC) presents a complete thought and can stand alone as a sentence.
A dependent clause (DC) does not present a complete thought and cannot stand alone.
Sparrows make nests in barns (I C) so that they can stay warm during the winter (DC).

3. Introductory phrases or clauses
Use a comma after an introductory phrase or clause. In the coldest weather, they made a snowman. Introductory phrase Independent clause Although they got cold, they made a huge snowman! Dependent and Independent clause Introductory clause

4. IC, conjunction IC
Use a comma between two independent clauses (IC) that are joined by a conjunction (CONJ). Conjunctions: and, but, nor, yet, so, or I wanted to go outside to play, but it was freezing! (IC) CONJ (IC)