Output is now six times___it was before liberatoin.为什么填what,这里面的从句没有动词啊,求详细的讲解

Output is now six times___it was before liberatoin.
为什么填what,这里面的从句没有动词啊,求详细的讲解

这里what是作宾语,引导宾语从句, it指代output是形式主语,意为 现在的产量是解放前产量的六倍.完整的说法可以是Output now is six times the amount of what it was before liberation.表达倍数的方式：这用的是倍数+ the +名词 (size/length/width/height...)of...的结构