what引导什么从句？同位语从句吗？该句子怎么翻译？（10.2.2）

Question

To make full use of the dictionary, one needs to have a good idea what exactly it contains.

Answer 1

what
exactly
it
contains
是idea（名词）
的同位语，叫做同位语从句，它解释
idea。该句话可以译成：为了充分利用这本词典，人们需要很好地了解它到底包含些什么。

Answer 2

To
make
full
use
of
the
dictionary,
one
needs
to
have
a
good
idea
of
what
exactly
it
contains.为了充分2113利用字典，人5261人需要能清楚4102它确1653切包括那内些（内容）。have
a
good
idea
of
---清楚了解，what
exactly
it
contains宾语从句容。