a is to b what c is to d中的what 是关系代词但它引导的是什么从句?

a is to b what c is to d中的what 是关系代词但它引导的是什么从句? A is to B what Cis to D(A与B的关系犹如C与D的关系)中的what 是关系代词但它引导的是什么从 A is to B what C is to D 的句式中WHAT引导的是什么从句 A is to B what C is to D 的句型,将what从句放句首 A is to B what C is to D 的句型,将what从句放居首 “A is to B what C is to D”句型,what起什么成分作用?这是从句吗? A is to B what C is to D what 在句中是什么成份? A is to b what c is to d A is to B as/what C is to D 请问：1.A is to B ,what C is to D.what 是做什么词? A is to B what C is to D 是什么句型? what A is to B is what C is to D