Mom flew to Chicago and land at O’Hare International Airport, one of the busiest airport in the U.S . Is this a Long introductory Element? Or an appositive? Or an item in a series? Or a compound sentence?

This is a long introductory element.

If I win ticket to the concert, I will go with my best friend. From the same selection from the previous question, what is it?

This is a compound sentence.

You sure? It didn’t even have a conjunction

Apologies for the confusion. You are correct, it is not a compound sentence. It is actually a complex sentence. "If I win ticket to the concert" is a dependent clause (subordinate clause) acting as a conditional adverbial clause, while "I will go with my best friend" is the independent clause (main clause).

So it would be a appositive phrase.

I apologize for the confusion in my previous response. Upon reviewing your statement again, "If I win a ticket to the concert, I will go with my best friend," it is not an appositive phrase either. It is indeed a dependent clause (conditional adverbial clause) followed by an independent clause (main clause), making it a complex sentence. Thank you for pointing out the error, and I apologize for any confusion caused.

What about a introductory element?

Apologies for the oversight in my previous responses. "If I win a ticket to the concert" can indeed be considered a long introductory element. It functions as an introductory subordinate clause, providing context or setting a condition for the main clause "I will go with my best friend." Thank you for your patience and for bringing this to my attention.

But you said the other sentence was a introductory element so which one is a introductory element and what is the other one?