楼上的人都不对.不是宾语从句,depicting happiness也不是拿来修饰the one的.
1.what is the one // modern form of expression almost complitely dedicated to depicting happiness?句子应该这样割开.
2.what is the one是句子的主句,后面的部分就算省略,也不影响句句子重要成分主语one和谓语动词is 的缺失.
3.modern form of expression almost complitely dedicated to depicting happiness可以说是一个独立主格结构.因为be dedicated to + doing 是一个固定词组,意思是“奉献给”,这个词组直接用形容词组,在此后置,修饰modern form of expression.
4.modern form of expression almost complitely dedicated to depicting happiness 整个修饰主语the one.
5.这个句子大概可以翻译成：必竟,现代语言表达中完全用来描述快乐的词是哪一个呢?