来自路峰的问题
secondaryschoolintheUSusuallycoverssevenyears,gradessixtotwelve这句子里cover为什么要加s变covers?还有lighttravelsfasterthansound那个travel为什么要加s?
secondaryschoolintheUSusuallycoverssevenyears,gradessixtotwelve这句子里cover为什么要加s变covers?
还有lighttravelsfasterthansound那个travel为什么要加s?
1回答
2019-05-01 11:22