【题目】Was it through Mary _____ was working at a high school _____ you got to know Tom?
A.who; whom
B.that; which
C.who; that
D.that; who

【答案】C
【解析】考查定语从句及强调句。句意：你是不是通过正在高中工作的玛丽认识汤姆的？第一空引导非限制性定语从句，修饰先行词Mary，并在从句中作主语，故用who; 第二空用that，与Was it through Mary 一起构成强调句的一般疑问形式，被强调部分是作方式状语的介词短语through Mary.故C项正确。