Four main types of sentence structures in English:

Simple
Compound
Complex
Compound-complex

Simple Sentence

1 independent clause

e.g., "I like speaking English."

[independent clause]

Compound Sentence

2 or more independent clauses joined by a conjunction (e.g., "and", "but", "or")

e.g., "I like speaking English, and I also like reading it."

[independent clause] + [conjunction] + [independent clause]

Complex Sentence

1 independent clause and 1 or more dependent clause

e.g., "I will practice speaking with a native speaker because I want to improve my fluency."

[independent clause] + [dependent clause]

e.g., "Because I practice speaking English every day, my fluency has improved significantly."

[dependent clause] + [independent clause]

Compound-complex Sentence

2 independent clauses and 1 or more dependent clause

e.g., "Although she practiced her vocabulary every day, Maria still struggled with English idioms, and she eventually asked her tutor for help."

[dependent clause] + [independent clause] + [conjunction] + [independent clause]

e.g., "The students finished their grammar exam, but they stayed in the classroom because the teacher was about to review the answers."

[independent clause] + [conjunction] + [independent clause] + [dependent clause]

e.g., "Because she wanted to improve her fluency, Sarah watched English movies every weekend, and she kept a vocabulary journal whenever she learned a new word."

[dependent clause] + [independent clause] + [conjunction] + [independent clause] + [dependent clause]