__is known to us all is that the old scientist,for___life was hard in the past,still works very

问题描述:

__is known to us all is that the old scientist,for___life was hard in the past,still works very
hard in his eighties.
为什么是what whom
第一个为什么不能用as
第二个为什么是whom

第一个引导的是主语从句,第二个引导的是表语从句 所以用what whom第一个懂了,为什么第二个不能用whosefor whom=whose 例如有的题里能遇见for which=why