Compound and Complex Sentences
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A simple sentence has one subject and one predicate.

Examples:
My dog likes treats.
Apples are delicious.
Tomorrow is Sunday.
My brother is five years old.
Kevin read a book about ocean life.



A compound sentence is two sentences joined with a conjunction (and, but, or) and a comma.

Simple sentence: I love cookies.
Simple sentence: Cookies are not healthy treats.
Compound sentence: I love cookies, but they are not healthy treats.

Since I am combining two sentences with a conjunction (but), I need to add a comma before the conjunction.

Compound sentence examples:
I love cookies, but they are not healthy treats.
Cats are mammals, and they have four legs.
Paris is a beautiful city, but it is very expensive.
I could go to the movies, or I could watch a baseball game.
Do you want to go swimming, or would you rather stay home?



A complex sentence is a sentence joined to a fragment with a conjunction or transition word. Remember, a fragment does not make sense on its own.

Simple sentence: I brushed my teeth.
Fragment: Until they were clean.
Complex sentence: I brushed my teeth until they were clean.

The fragment "until they were clean" doesn't make sense on its own.

Simple sentence: Joe left for the park.
Fragment: After his mom got home.
Complex sentence: Joe left for the park after his mom got home.

Complex sentence examples:
After the storm passed, the grass was very green.
I fell when I tripped over a rock.
Karen read a book while she waited for the bus to arrive.
Whenever I am at Grandma's house, I always eat a lot of candy.
If an animal has feathers and wings, it is probably a bird.

In these examples, the fragment is underlined. The fragment will not make sense on its own. The simple sentence is not underlined, and it will make sense on its own. The fragment adds more information to the sentence.