A is to B what C is to D 的句式中WHAT引导的是什么从句

题目

A is to B what C is to D 的句式中WHAT引导的是什么从句

答案

引导比较状语从句
A is to B,what C is to D或者
What A is to B,so is C to D
As a is to B,that C is to D
翻译成,A和B的关系正如C和D的关系一样
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