Identifying Simple, Compound, Complex and Compound Complex Sentences

Simple Sentences have one independent clause. A simple sentence does not need to be a short sentence. It can also be a sentence. It may have FANBOYS in the sentence if the function of the FANBOYS are not to connect 2 ideas.

For example:
I'm not finished yet.
The word yet is not function to show contrast, thus the sentence is not a compound sentence.

Mommy buys some toys for me.
The word for is not function to show cause effect, thus the sentence is not a compound sentence.

Compound Sentences have two or more independent clauses which are connected with a coordinated conjunction (FANBOYS) - For (to show cause and effect), And (to show additional information), Nor (to show preferences in negative sentence), But (to show contrast), Or (to show preferences in positive sentence), Yet (to show contrast) and So (to show cause effect).

For example:
She's crying for her broken heart (the function of for is to show cause effect)
I work and play hard (the function of and is to show additional information)
Johnny does not like tea nor coffee (the function of nor is to show preferences in negative sentences)
Mary loves you but she hates your style (the function of but is to show contrast)
They want some food or drink to break the fast (the function of or is to show preferences in positive sentences)
Lilith is so smart yet she has never finished her workshop (the function of yet is to show contrast)
I have got a stomache so I cannot eat spicy food (the function of so is to show cause effect)

Complex sentences have a minimum one independent clause and one dependent clause which are connected with subordinate conjunctions (ABE IS TUW) - After, Because, Even though, If, Since, Than, Unless, Which, etc.

For Example:
She arrived after I left the house
Jhonny is grinning because he got a good score on his assessment
There are times I want to scream even though I am smiling
If I were rich, I would buy an aeroplane
I have been feeling alone since you have been gone
Maria prefers coffee than tea
Unless you correct your mistakes, I would never revise your test result
Our family moved into an apartment building which is near the mall.

Online Exercises:
Exercise 1
Exercise 2
Exercise 3
Exercise 4