I found out that perennial and fundamental laws governing the art of good writing had been discovered.
I 主语
found out 谓语 一般过去时态
that...that 及其后为that引导的宾语从句
（perennial and fundamental前置定语） laws 宾语从句的主语
governing the art of good writing 现在分词V-ing短语后置作定语修饰从句主语...laws
had been discovered 从句谓语 过去完成时态的被动语态