任务型阅读，读下面的文章，并在后面的横线上填上相应的答案，使句意符合短文意见。

    What color are their sweaters(毛衣)?

    Kate, Jim, Rose and Bill put their sweaters on the table. The sweaters are white, blue, red and black. We know, the boy's sweaters aren't red and the girls' sweaters aren't black. What color is Kate's sweater? I don't know. But I know it is not blue. Bill says, “My sweater is white.” Then what color are their sweaters?