Air pollution has become the biggest (o ) inthe city now.这是缺词填空_英语解答

Air pollution has become the biggest (o ) inthe city now.
这是缺词填空

人气：479 ℃　时间：2020-04-12 18:35:18

解答

是O打头的?有没有语境啊,要是前面提到了的话,可能填one就可以了吧