OG13-17关于句末过去分词

Etoile-

过去分词在句首可以有连词，和主语表被动  连词，done，svo
想请教一下，过去分词在就近修饰的时候，过去分词前可否出现连词例如when while although even though等等

Sunspots, vortices of gas associated with strong electromagnetic activity, are visible as dark spots on the surface of the Sun but have never been sighted on the Sun's poles or equator.

                     


are visible as dark spots on the surface of the Sun but have never been sighted on




                     
are visible as dark spots that never have been sighted on the surface of the Sun




                     
appear on the surface of the Sun as dark spots although never sighted at




                     
appear as dark spots on the surface of the Sun, although never having been sighted at




                     
appear as dark spots on the Sun's surface, which have never been sighted on

OG解释c选项说

Although typicallyintroduces a subordinate clause,which has a subject and a verb, but here there is nosubject and sighted isnot a complete verb.

但是能不能理解成although作为一个连词，sighted过去分词修饰dark spot

虽然正确答案是A很明显，但是OG对C选项的解释看的我很懵逼，希望大佬们指教

emmahiggins09

这里的问题是，你的although 从句部分省略了从句的主谓，这里可能是说 dark spots have never been sighted 也有可能说的是although sunspots have never been sighted，表达有歧义不清晰。

RON说过好几次了，OG语法部分的解释不用看，看了误人子弟。