单选题
With facilities worth 30 to 50 billion dollars and 9,000 miles of roads in the national ______ park system alone, keeping up with needed repairs is.
【正确答案】
B
【答案解析】[解析] 形容词词义辨析。根据题干中30 to 50 billion dollars，9,000 miles提供的信息，此处是指这个park system巨大的花费是令人吃惊的，只有appalling(可怕的；令人震惊的)符合要求。故答案为B。