How should I describe the sentence?

[Maybo]

The greatest percentage of homes without power is in Suwannee County, an inland area in Florida's north.

Source: Number of Floridians without power jumps to 265,000 by BBC


I just had an English class. In the class I read a writing and I had a question about sentence structure. I want to ask my teacher about that but I don't know how to describe the sentence. The above sentence is not related to the writing. I just take that for example.

My question is "how do I describe the sentence before the comma?" Preceding clause or sentence? Or should I just say the clause before the comma?

 

[Tarheel]

The phrase you are looking for is "independent clause". That is, it would be a sentence all by itself without the additional information tacked on at the end.

 

[Maybo]

The phrase you are looking for is "independent clause". That is, it would be a sentence all by itself without the additional information tacked on at the end.

How do you describe the part after the comma?
For example, I don’t understand the part before the comma and ask my teacher to clarify it, can I say “I don’t understand the part before the comma”?
If I don’t understand the part after the comma, can I say “ I don’t understand the part after the comma”?

 

[Tarheel]

Those are OK.