Which skirt is Helen's?
Whose is this red skirt?对第二句海伦的提问要写两句你写了一句按照你上面的句子，只能做一个句子。如果一定要做的话，那就是Whose is this red skirt?的同义句，Whose red skirt is this?能写Whose skirt is this red不行。但下面的这句也行：Whose skirt is red?