都是正确的.doesn't 拼写有点问题my brother has no interest in cartoons。这句里的in就是指在某方面，而be interested in 是固定搭配对吧，有人说have/has no interest in =be interested in ,也就是这两句做同义句比较好 my borther is not interested in cartoons；my brother has no interest in cartoons。是这样吗？interest作名词， interested作形容词，两者后面都搭配介词in。如：show interest in,对...表现出兴趣；become interested in，变得对...感兴趣