I was reading this article and there are a couple of spots that I don't understand when it comes the grammar.
専門家は「雄と雌の体を持ったカブトムシが生きているところを見たのは初めてです」と話しています。
Roughly: The specialist said 'It is the first time I have seen a beetle that has a male and female body'
Why/What is the purpose of the bolded の? Why does it comes after 見た? の particles that look like this come up a few times in the article actually
The の particle we're talking about here is a nominalizer, basically it turns verbs into nouns, so that you can work with them in the way you work with nouns, like turning them into topics, subjects, direct objects, and so on.
I'll try to illustrate some quick examples here:
鳥を見た。 - Tori wo mita. (I saw a bird)
彼が走っているのを見た。 - Kare ga hashitteiru no wo mita. (I saw him running)
You can't use the direct object particle 「を」 with a verb 「走っている」, so you use 「の」 in order to get that result.
That applies to all different particles, like は for instance:
数学は難しい。 - Suugaku wa muzukashii. (Math is hard.)
野菜を食べるのは難しい。 - Yasai wo taberu no wa muzukashii. (It is hard to eat vegetables.)
Once more, 「の」 is nominalizing the verb 「食べる」 so that you can use the particle 「は」 with it.
