We’re talking about the piano and the pianist were in the concert we attended yesterday.
A. which
B. whom
C. who
D. that
网友回答
A. which
B. whom
C. who
(答案→)D. that
解析：考查定语从句。本题定语从句的先行词是 the piano and the pianist,先行词中既有人也有物，故使用that作为关系代词，指代先行词在句中做主语。Which只能指物；whom，who只能指人；故D正确。