请高人分析这个句子结构

问题描述:

请高人分析这个句子结构
They found what they thought to be lumps of coal but that turned out to be papyrus scrolls.这里的but that是作什么?我觉得把but that去掉更合理些吧?

应该把 but that 去掉.因为 they thought to be lumps of coal 修饰 what.即如果不去掉 but that:They (主语)found (谓语)what (引导宾语从句,found 的宾语,并做从句中thought 的宾语) they (宾语从句主语)th...