He had waited until she had finished her work.

He had waited until she finished her work.

以上二个句子有细微差别。假定she完成工作的时间为五点十分。第一句表示他等到五点十五分左右，见到了她，等待的动作结束。

第二句则表示他等到她五点十分干完活，结束等待。

第一句之所以用二个过去完成时，是因为说话人心目中关注的时间是五点十五分他见到她这个时间，而等待wait和finish这二个动作都是在五点十五分之前发生的。所以主从句都用过去完成时。但实际上，until从句用一般体和完成体的时间差异很小，通常被人们忽略，因此通常在until从句用完成体较少。有的语法书甚至认为用完成体和一般体意义相同。这是忽略细微的时间差别。

以下四个句子意义相差不大，或者说可以忽略他们之间的差别：

He had waited until she had finished her work.

He had waited until she finished her work.

He waited until she had finished her work.

He waited until she finished her work.