To write well, it helps to understand how sentences are structured. Here, we’ll look at compound predicates and how they differ from compound sentences.
Every full sentence (or clause) should have a subject and a predicate:
A standard predicate will have a single main verb or verb phrase. But a predicate can contain more than one verb or verb phrase, all of which describe the same subject. This is known as a compound predicate.
A compound predicate can be as simple as two verbs joined by a conjunction:
The doors creaked and rattled.
Here, for instance, the subject is “doors,” with the verbs “creaked” and “rattled” forming a single predicate (i.e., both words refer to what the doors are doing).
But sometimes a compound predicate can be more complex:
The symphony starts softly, builds to a crescendo, and ends with a flourish.
Here, the predicate contains three verbs (i.e., “begins,” “builds,” and “ends”), but it also contains modifiers that tell us more about the actions they describe.
A compound predicate can contain as many verbs and modifiers as you like. But long sentences can be hard to read, so it’s best to use lengthy predicates sparingly.
Like a compound predicate, a compound sentence will include more than one verb (or verb phrase). But these “compounds” are different in other ways, including in how they should be punctuated. Let’s take a look at the difference.
In a typical compound sentence, two (or more) independent clauses are joined by a conjunction. And to show that they are separate clauses, we add a comma before the conjunction. For instance, we could say:
Sam ate breakfast, and then she walked the dog.
Here, rather than a single clause with a compound predicate, we have two distinct independent clauses (i.e., each clause would work as a sentence by itself). In the first, the subject is “Sam” and the predicate is “ate breakfast.” And in the second clause, the subject is “she” and the predicate is “walked the dog.”