请教这个英文句子的结构分析及翻译，谢谢！

Question

请教这个英文句子的结构分析及翻译，谢谢！
It has been claimed that the technologies shown by some early civilizations could only have been learned from people from another planet. (Chambers)

Answer 1

据宣称,一些早期文明中所创造出的技术只能从外星人那里学习了(钱伯斯)
It has been claimed that....这是一个主语从句,也就是说从句子的整体来说,that 后的成分都是整句话的主语,由于主语太长所以用it代替,it是一个形式主语,正常的语序应该是the technologies shown by some early civilizations could only have been learned from people from another planet has been claimed
再来分析主语这一句话the technologies shown by some early civilizations could only have been learned from people from another planet
这句话中the technologies shown by some early civilizations 是主语, could only have been learned 是谓语,而该句没有宾语,from people from another planet是这个句子的状语
再来看the technologies shown by some early civilizations ,这是一个词,technologies 是主干,shown by some early civilizations 是他的后置定语起修饰作用,
至于 could only have been learned,这是一个虚拟语气的用法,因为这个句子所陈述的事实是猜测,所以需要用虚拟语气,就是could+have/has done

我很认真的在讲解,你就采纳了吧

Answer 2

据宣称，一些早期文明所显示出的技术只能是从来自其他星球的人类学来的。

Chambers ['tʃeimbəz]
基本翻译
n. 钱伯斯（姓氏）本回答被网友采纳

Answer 3

句子的意思：据宣称，一些早期文明出现的技术只能是从来自其他星球的人类学来的。句子的主要成分是the technologies could only have been learned from people from another planet.这个是it做形式主语，that之后的从句做真正主语的句子，相当于 it is said that......（据说......） 句型一样,shown by some early civilizations 在句子中做the technologies的定语。

Answer 4

这是一个主语从句it是形式主语真正的主语是句子 that the technologies shown by some early civilizations could only have been learned from people from another planet 。在这个句中shown by some early civilizations 是过去分词短语作为后置定语来修饰the technologies ， 而could only have been learned from 作为从句的谓语，其could have been learned 结构是情态动词表示推测的用法；而people from another planet是从句的宾语。
整个句子可译为：有人主张，一些早期文明所表现出的技术可能只是向来自其他星球的人类学习来的。

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It has been claimed that the technologies shown by some early civilizations could only have been learned from people from another planet. (Chambers)