你理解有误...
It is only a dream, isn't it? 这只是个梦想,不是吗?
肯定：yes,it is 是的,它是梦想
否定：no,isn't不,它不是梦想
如果前面是否定的,后面反问,就不一样了..
It isn't only a dream, is it? 这不只是个梦想,是吗?
否定：yes,it is 不,它只是梦想
肯定：no,isn't是的,它不只是梦想