though在句中的词性和理解

老师好！

Though much more difficult to understand than the traditional paintings, they were more thought-provoking.

我是这么理解的，though本身既能做连词也能做副词，在本句中，因为“Though much more difficult to understand than the traditional paintings,”缺少主语，因此是副词，但though做副词通常都是做句中或句尾同时需要用逗号隔开，就矛盾了，请老师解惑！谢谢！

though作为连词引导让步状语从句。省略了和主句相同的主语和be。还原主语和be则为：

Though they were much more difficult to understand than the traditional paintings,they were more thought-provoking.