【题目】- Got it! This is the first step______the engineer went wrong．
- Oh， one fault may lose everything．
A. whichB. where
C. thatD. when
在线课程【答案】B
【解析】
考查定语从句。句意：——知道了!工程师一开始就出现了错误。 ——哦，一着不慎，满盘皆输。______the engineer went wrong．是一个定语从句，the first step是先行词，关系词在定语从句中作地点状语，表示“在第一步就出现了错误”，所以用关系副词where，故选B。