Its wool had been washed clean by the rain.which had been dy

这里的clean和black都是形容词,做主语its wool的补足语.我们把句子改成主动句:The rain had washed its wool clean,which people had dyed black.(which people had dyed black 逻辑上=people had dyed its wool black.) 这样就清晰多了.
再问： 等于都是双宾语 形容词可以直接坐宾语？ which people had dyed black 也就是说dye的间接宾语可以省略？
再答： 看来你把“宾语和宾语补足语”的关系和“双宾语”混为一谈了。“宾语和宾语补足语”的关系和“双宾语”是完全不同的。形容词当然不能做宾语！这哪里是双宾语啊？！ 【俊狼猎英】团队为您解答。