What phrase structure rule creates coordinate structures?

I am confused here. Is it prepositional phrases?

I think I got it. The simple sentence phrase rule is used to combine compound sentences. Is this correct?

I have no idea what your text is saying, but I think you're confusing phrases with clauses.

Phrase = a group of words, used as a unit in a sentence (prepositional phrase, adjective phrase, etc., etc.) = without subject and verb
http://www.chompchomp.com/terms/phrase.htm

Clause = a group of words, used as a unit in a sentence, which DOES have a subject and verb. Clauses can be either dependent/subordinate or independent/main.
http://www.chompchomp.com/terms/clause.htm

Simple sentence = 1 independent clause
Compound sentence = 2 independent clauses joined by a semicolon or by a coordinating conjunction
Complex sentence = 1 independent clause + at least 1 dependent clause
Compound-complex sentence = a compound sentence + at least 1 dependent clause

I mean the phrase rule

sentence=Noun phrase, aux, verb phrase

That is the phrase structural rule. I understand what you wrote but I can't connect it with what am trying to figure out. Can you please explain?

This seems to be phrasing specific to your text: "What phrase structure rule creates coordinate structures?"

I have no idea what that means!!

Okay, thanks for the quick response!

Sorry I don't understand that one. Sometimes I think people write new books with new terminology just to sell textbooks! =)

I don't know if you'll return to find this, and I don't know if this will help at all -- but if the task is to create coordinate structures in English, usually we use commas and coordinating conjunctions:

http://grammar.ccc.commnet.edu/grammar/conjunctions.htm#top

If you give some specific examples, it would be easier to tell if this is what is meant. Does your text include any examples?