Output is now six times _____ it was before liberation.

问题描述:

Output is now six times _____ it was before liberation.
(A) that (B) which (C) what (D) of which
并请说明依据,

首先排除BD 因为这句话不是定语从句 然后看从句缺少表语 既能引导从句又能在从句中做成分的只能是C