as is often the case 这是什么语法现象?省略?倒装?

解释一个句子的语法As is often the case with elder people ,my grandma As the case is often和As it often the case As is it 和As it is She is absent, as is often the case.译文 as is often the case,we have worked out the As is often the case,whenever i spoke,he spoke. As is often the case,we have worked out the plan.这句话怎么翻译呢? As is often the case和A case in point is Li Ming is late, as is often the case中as为什么不能用which替代 句中的as什么用法 充当什么角色 As is often the case with. as is often the case的语意及as的全方位综合用法 【急】as is often the case中的as为什么不能换做which as is the case with .