Usage and Grammar

Q. Convoluted structure aside, is there anything grammatically wrong with the following sentence from a state unemployment application? My boss thinks “which” is incorrect and should be replaced with “that”; I think both are incorrect. Please help! “Did you work full-time or part-time for an employer or in self-employment or return to full-time work during the week ending last Saturday, which you have not already reported?”

A. The sentence is ungrammatical, because “which” has no antecedent. Changing it to “that” does not help. Adding a noun somewhere (such as “hours”) and moving things around will fix the grammar. “During the week ending last Saturday, did you work any hours (full-time or part-time, for an employer or in self-employment) that you have not already reported, or did you return to full-time work?” Either way, “that” is preferred, but “which” is not incorrect.