该句子的主干是voices now come from many quarters；句首Just as结构做比较状语，意为"正如...一样"；insisting 引导的分词结构做定语修饰主语voice，分词结构中含有两个并列的由that引导的宾语从句，第二个宾语从句的真实主语是不定式结构to keep... 翻译：就象吸烟问题一样，来自不同领域的声音坚持认为有关全球变暖的科学资料还不完整。

Just as on smoking, voices now come from many quarters insisting that the science about global warming is incomplete, that it's Ok to keep pouring fumes into the air until we know for sure。

youdao

spoken是动词speak的过去分词形式，在句中作定语，修饰主语language, spoken 与 language有被动关系。该句可以理解为

What’s the language (which is) spoken in German?

youdao

现代的英语教材中常常使用分词或分词短语作修饰语。

Participles and participial phrases are usually used as modifiers in modern English texts.

youdao