如何將nsmutableattributedstring轉換為nsstring

NSString * aString = @ "妳好，世界！"；

NSMutableAttributedString * attributedString =[[NSMutableAttributedString alloc]init withstring:string attributes:nil]；

[attributed string set attributes:@ { NSForegroundColorAttributeName:[ns color red color]} range:NSMakeRange(0，5)]；

//NSMutableAttributedString到NSString

ns string * another string =[attributed string string]；