It ______in this new hall ______ was just set up last month ______ we held an important meeting yesterday.
A.is; which; thatB.was; which; whatC.is; that; whichD.was; which; that在线课程D
解析：
考查强调结构及定语从句。根据时间状语last month，故用过去时态，故用it was +强调部分 + that；
第二空考查定语从句，先行词为new hall，在从句中作主语，故选D。