Expedient in this excerpt means for something to be appropriate to a purpose.
Answer:
It is grammar. Just search Google.
Explanation:
Google has a document like that with the answers
Antecedent of a pronoun is a word that the pronoun refers to, or replaces. So, in this sentence, we are looking for the antecedent of the pronoun IT. The pronoun IT replaces the noun Chicago, which means that the word Chicago is the antecedent of the pronoun IT.
IT provides the best opportunity, meaning that Chicago does that.
Write for your reader, not yourself.
Use pronouns when you can.
State your major point(s) first before going into details.
