问题补充：
---- Could you tell me ? I’m going to visit him.
---- Sorry, I don’t know.
A. which school does Peter work at
B. which school did Peter work at
C. which school Peter works at
D. which school Peter worked at
答案：
A. which school does Peter work at
B. which school did Peter work at
(答案→)C. which school Peter works at
D. which school Peter worked at
解析：句意：请你告诉我彼得在哪一所学校工作，好吗？我要去拜访他。很抱歉，我不知道。在宾语从句位置上只能用陈述句语序，不能用疑问句语序。当主句为一般现在时时，宾语从句可以根据表达需要使用不同的动词时态，但主句为一般过去时时，宾语从句必须使用相应的过去时态，当然从句表示客观真理时要用一般现在时。Could you tell me…？中的could只表委婉语气，不表过去时态。
