Question: Which of the following airports is closer to the city center of Beijing City: Beijing Xijiao Airport or Beijing Capital International Airport? 
Sentence (from "Beijing Airport Bus"): One way fare on routes to the city is ¥16 (¥24 to Beijing South Station as of April 2015) and varies from ¥40 to ¥140 on routes to Tianjin and cities in Hebei.
Relevant evidence: No