A complex compound sentence is a sentence that contains at least one dependent clause and two or more independent clauses. Here are some examples:

1. Although it was raining, I decided to go for a walk, and I brought my umbrella just in case.
2. She studied hard for the exam, but she still didn’t get a good grade because she didn’t understand the material.
3. After finishing his work, he went to the gym, and then he met his friends for dinner.
4. The dog barked loudly when the mailman arrived, so the mailman quickly left the yard.
5. I enjoy reading books, but I also love watching movies because they transport me to different worlds.

In these examples, the dependent clauses are “Although it was raining,” “because she didn’t understand the material,” “After finishing his work,” “when the mailman arrived,” and “because they transport me to different worlds.” The independent clauses are “I decided to go for a walk,” “I brought my umbrella just in case,” “She studied hard for the exam,” “she still didn’t get a good grade,” “he went to the gym,” “he met his friends for dinner,” “The dog barked loudly,” “the mailman quickly left the yard,” “I enjoy reading books,” and “I also love watching movies.”