一句子的翻译

定语，过去分词作定语
可以写成would you have told him the answer which had been possible?
这句话中只是省略了which

你已经告诉他可能的答案了吗？

在句子中修饰 answer

你告诉过他这个可能是的答案吗？
had been possible 在句子中修饰the answer ，这个句子可以改为
would you have told him the answer which had been possible?

would you have told him the answer had been possible

意思是说 你是不是已经告诉了他可能发生的答案（结果）？

做定语

不是宾语从句,是定语从句,修饰名词answer
省略先行词that