很明显,第一个是对的,第二个是错的.
at school是副词,只能用be动词连用构成主系表结构.如：He was at school yesterday.
不能说did...at school.因为did是助动词,后面必须跟实意动词,很明显,第二个句子中没有实意动词（at是介词,school是名词）.但可以这么说：Did hegoto school yesterday?