同学你好，该知识点来自沪江网校《新概念英语1、2、3、4册连读【全额奖学金班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
The most valuable find of all was the ship's log book, parts of which it was still possible to read.
这里it是形式主语，换一下顺序是
it was still possible to read parts of which
不能去掉it，否则这个句子就成了parts of which was still possible to read
而possible后面要加to do的话，主语通常是it，it is possible to do sth
所以这里it不适合省略。

祝同学学习进步~