Mr. White has become bad-tempered since he indulges in Gambling. He is no longer the man______ used to be.
【正确答案】 D
【答案解析】考查定语从句。由于先行词是the man，可先排除A项which。分析句子结构，关系代词在从句中作表语，这时只能用that引导定语从句，故选D，同时排除B和C。