Make a compound-complex sentence by joining two complex sentences, or one simple sentence and one complex sentence together. Worded differently, this type of sentence has at least three clauses: two or more independent clauses and one or more dependent clauses.

There are several ways to attach an independent clause to the rest of the sentence: coordinating conjunctions, correlative conjunctions, conjunctive adverbs, or semicolons.

Why would you want to use such a difficult-to-create sentence? Compound-complex sentences help people describe longer, more complicated thoughts. Authors may need to use this sentence type to explain complex ideas or to list long chains of events.

Here are some example compound-complex sentences with their dependent clauses in bold:

Sawyer is suspicious of hamburgers because of their high fat content, so she does not eat them.

While Jeff reads books, John reads blogs, and Steph only reads newspapers.

I couldn't pick my 6-year-old son up at school, but I wasn't worried since he knows his way home.

It was dark in the woods at night, so I used a flashlight and was able to get there on time.

Sir John A. Macdonald had a serious drinking problem; when sober, however, he could be a formidable foe in the House of Commons.

Construction examples

The two following sentences will be used as the basis to create compound-complex sentences:

Since I'm health conscious, I eat homemade meals. I eat at health restaurants, too.

The first sentence above is a complex sentence, and its dependent clause is bolded. The second sentence is a simple sentence (a typical independent clause). These two sentences will now be fused using a coordinating conjunction, a correlative conjunction, a conjunctive adverb, and a semicolon, bolded below:

Since I'm health conscious, I eat homemade meals, and I eat fitness snacks, too.

Since I'm health conscious, not only do I eat homemade meals, but I also eat fitness snacks, too.

Since I'm health conscious, I eat homemade meals; moreover, I eat fitness snacks, too.

Since I'm health conscious, I eat homemade meals; I eat fitness snacks, too.

There's no limit to how many clauses a complex-compound sentence can have. Take, for instance, this example with its independent clauses in bold:

Since I'm health conscious, I eat homemade meals, and I eat fitness snacks, too; however, I have been known to cheat from time to time and eat a big juicy hamburger, often on a Saturday.