Your children have learned about simple and compound sentences. Simple sentences combine subjects and predicates to make a single independent clause. When at least two simple sentences are joined by a comma and a coordinating conjunction, they become compound sentences. Things get a little more complicated when they start writing complex sentences.
Compound v. Complex Sentences
Complex sentences, like compound sentences, combine two clauses, but one clause is dependent while the other is independent. Dependent and independent clauses both have subjects and predicates, but dependent clauses cannot stand alone as an independent clause because they start with a subordinate conjunction.
There are many subordinate conjunctions. Many of them also serve as prepositions when they are not part of a dependent clause that has a subject and predicate. Some examples of subordinate conjunctions include after, before, because, even if, even though, if, since, until, when, whenever, and while.
Complex sentences may or may not have commas. When sentences start with a subordinating conjunction that forms a dependent clause, a comma appears at the end of the dependent clause before the beginning of the independent clause that follows. Sentences that end with the dependent clause do not have commas. Here is an example of two different complex sentences with the same meaning but different punctuation.
Since Jillian came to dinner, mother sat out an extra plate. This sentence starts with the dependent clause, so a comma is included before the independent clause.
Mother sat out an extra plate since Jillian came to dinner. This sentence ends with the dependent clause, so no comma is needed in the sentence.
Examples of Complex Sentences
To help your children understand the difference between simple, compound, and complex sentences, check out these easy examples.
Simple: Brendan cooked a meal for his family.
The subject is Brendan, and the predicate is cooked. There is one independent clause.
Compound: Brendan cooked a meal for his family, for they were very hungry.
The sentence contains two independent clauses. The first independent clause contains the subject Brendan and the predicate cooked. A coordinating conjunction, for, joins the second independent clause. The second clause has the subject they and the predicate were, a helping verb.
Complex: After Brendan cooked a meal for his family, they thanked him for his efforts.
This sentence contains a dependent clause with the subject Brendan and the predicate cooked as well as the independent clause with the subject they and predicate thanked.
Complex sentences really aren’t that complicated once your children get used to them. Differentiating between simple, compound, and complex sentences is the first place to start! Try out a few exercises to help them identify and write complex sentences.
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