( )6.- Do you know when he will come back - ____ .
( )6.- Do you know when he will come back ____ .
A.Once a week B.For a week C.Till a week D.Not until next week为什么选D请详解,
8.The factory which I visited yesterday was not the one where I once worked .
这是由which引导的定句从句+where引导的地点状语从句吗?