Complex sentence: Area code 217 is the North American telephone area code for much of central and western Illinois, including its capital city of Springfield, as well as Champaign, Urbana, Decatur, Danville, Quincy, and Rantoul.
Split into simpler sentences: Area code 217 is the North American telephone area code for much of western and central Illinois. The 217 area includes Illinois' capital, Springfield, plus Champaign, Urbana, Decatur, Danville, Quincy, and Rantoul.