This is a book,which I dare say,is unequaled as far as trans

1。This is a book主句,陈述句
2。which I dare say插入语
3。is unequaled as far as translation practice is concerned。定语从句,修饰book=
This is a book which is unequaled as far as translation practice is concerned。
4。as far as translation practice is concerned。定语从句里的状语
再问： 非常感谢您详细的解答。我还想问一下，as far as 在这里做介词还是连词？我最近对这个词组好迷惑。。。
再答： as far as这里不是介词作用也不是连词作用，是副词作用。
再问： 我好像终于碰见个明白人了。我再多问一点啊， this is as far as we go。 中的as far as 是什么情况？这是一个表语从句的结构吗？ 有人告诉我说 as far as 在这里做连词， 对吗？ as far as 什么时候 做介词，连词，副词呢？
再答： 1。this is 是一个系表结构，as far as we go是表语 2。其实这个句子是this is far，那么有多far呢?和we go一样，这样可以看出as。。。as wo go起到副词修饰far的作用