i knew she had been absent all week

问题描述:

i knew she had been absent all week
这个是过去完成时吧?knew 后面省略了that是吗?为什么省略?
为什么要加been?

因为 absent 是形容词 是 be+形容词 的句型.
She is absent.现在式
She had been absent.过去完成式.is 变成 had been
that 当连接词时,可以省略.