dunring the days that followed,that为什么不能去掉

.that followed = that happened later,虽然短但是一个完整的“定语从句”,that 既是引导从句的关系代词,同时也是从句的或...followed 的主语,是不可以省略的.如果是做从句宾语,是可以省略的：
e.g.I won't forget the days (that/which) I spent in the host family in the US.
这里就可以省略了:I spent that/which=the days in the host family.
明白?
其次,to follow,vi,接下来,随后发生,是不及物的,不能也无需用被动语态.
就像：This book belongs to me.
为什么说：This book is belonged to me.道理是一样的.
不是“被接下的数日”,就是“在随后的几天里”
可以改成：during the following/coming/ next days