I ______(not know) you _______(be)so busy in the past few years.怎么填
问题描述：
I ______(not know) you _______(be)so busy in the past few years.怎么填
答
don't know being
因为know很明显是句子的谓语，所以后面的be就不能用原型，只能是用现在分词作状语
答
didn't know had been
答
I did not know you were so busy...