iIt took me two weeks to finish reading the novel written by Mark Twain.为什么用written

问题描述:

iIt took me two weeks to finish reading the novel written by Mark Twain.为什么用written
为什么用written 而不用 was written

这里的written 是过去分词作定语.
如果用was written 则构成定语从句,应该是这样的:
It took me two weeks to finish reading the novel 【that was written 】by Mark Twain.