Anditsfastbecomingon的精选

问题详情：(2020·湖北省黄冈市高三质量检测)Andit'sfastbecomingoneofthegreatestpublichealthchallenges________wefaceinthe21stcentury.【回答】that空格处引导定语从句，修饰先行词challenges，在从句中作宾语；由于先...