The difference between a compound sentence and complex sentence is that a compound sentence has two independent clauses and a complex sentence has one independent clause and one dependent clause.
A sentence is a group of words that has a subject and a predicate. A subject, centered on a noun, is what the sentence is about. A predicate, centered on a verb, tells what happens to the subject. It tells what the subject does or is.
The dog jumped over the fence.
In this sentence, the bold part is the subject, and the second part is the predicate.
Sentences are made up of clauses, or groups of words. An independent clause, like the one above, can exist independently and makes complete sense on its own. A subordinate or dependent clause, on the other hand, requires an independent clause. The italicized portion of this sentence is a subordinate clause.
Sentence #1: Because it was chasing a rabbit, the dog jumped over the fence.
Let’s look at that italicized portion without the independent clause holding it up.
Because it was chasing a rabbit.
This is not a sentence by itself. It needs the rest of the sentence to be a complete thought. That makes our rabbit sentence (Sentence #1) a complex sentence.
A compound sentence, on the other hand, is made up of two independent clauses. If we remove the word “because,” the sentence becomes a complete sentence.
It was chasing a rabbit.
Compound sentences are usually combined with a coordinating conjunction such as for, and, nor, but, or, yet, and so.
Sentence #2: It was chasing a rabbit, and the dog jumped over the fence.
In this sentence, both clauses are independent clauses. This means that each clause (It was chasing a rabbit) and (the dog jumped over the fence) are both complete sentences themselves. Combined together they become a compound sentence.
When you are writing, you want to vary the sentence structure you use to make your writing more interesting and sophisticated. Make sure you write in complete sentences, use clauses correctly, and keep your writing fresh.
Just to add a little more detail about compound sentences, there may be two or more independent clauses:
"I was very thirsty, and I wanted something refreshing; the lemonade stand a block down the street seemed more and more enticing."
In this case, there are three independent clauses. Two of them are separated by the comma and the conjunction and. The third is set off by the semicolon, which can also be used to separate independent clauses.
Variety is important, and good writers learn to manage their sentence structure using any combination/number of independent and dependent clauses. Just be sure to use the tools to separate them correctly, and strive for clarity.
Compound sentences are when 2 independent sentences are joined by a coordinating conjunction i.e for, and, nor, but, or, yet, so.
Example: I was waiting for the train to arrive but the train was late.
Complex sentence is made up of one independent clause and one or more dependent clauses. A dependent clause lacks one of the elements in order to make it a complete sentence. Dependent clause start with subordinating injunctions i.e. after, although, as, because, even though, even though, if, since, unless, until etc.
Example: I did not see them at the station because Mary and Samantha arrived at the bus station before noon.
A compound sentence is composed of two complete sentences/thought that are related and is joined by conjunctions (and, or, but, etc.)
A complex sentence, on the other hand, is composed of one complete sentence/thought and one phrase that is also related to the former. This kind of sentence usually presents cause and effect. Complex sentences are identified when because, when, if, etc. are used.