1. Simple, Complex, Compound and Compound-Complex Sentences

2. Independent Vs. Dependent
An independent clause simply means it can stand alone as a complete sentence.
A dependent clause means it cannot stand alone as a complete sentence- it needs to be paired with an independent clause.
After they finished studying

3. Simple Sentences Some students like to study in the mornings.
A simple sentence, also called an independent clause, contains a subject and a verb, and it expresses a complete thought.
Some students like to study in the mornings.
2. Juan and Arturo play football every afternoon.
3. Alicia goes to the library and studies every day

4. Compound Sentences
Conjunction Junction
A compound sentence contains two independent clauses joined by a coordinator (conjunction). The coordinators are as follows: for, and, nor, but, or, yet, so. (Helpful hint: The first letter of each of the coordinators spells FANBOYS.) Except for very short sentences, coordinators are always preceded by a comma.
I tried to speak Spanish, and my friend tried to speak English.
2. Alejandro played football, so Maria went shopping.
3. Alejandro played football, for Maria went shopping.

5. Complex Sentences
A complex sentence has an independent clause joined by one or more dependent clauses. A complex sentence always has a subordinator such as because, since, after, although, or when (and many others) or a relative pronoun such as that, who, or which
When he handed in his homework, he forgot to give the teacher the last page.
The teacher returned the homework after she noticed the error.
The students are studying because they have a test tomorrow.
After they finished studying, Juan and Maria went to the movies
Juan and Maria went to the movies after they finished studying.

6. Compound-Complex Sentences
A compound-complex sentence is made from two independent clauses and one or more dependent clauses.
Although I like to go camping, I haven't had the time to go lately, and I haven't found anyone to go with.
independent clause: "I haven't had the time to go lately“
independent clause: "I haven't found anyone to go with“
dependent clause: "Although I like to go camping... "

7. Simple, Compound, Complex, or Compound-Complex?
It rained for three days, so the streets in my neighborhood flooded.
Compound
Even though his heart pounded with dread, Ben bolted up the stairs, and he checked out the strange noise.
Compound-Complex
Frank had a good sense of humor, so he laughed a lot.
Complex
I stayed up late last night.
Simple