1.hardly had sb did when……应该是hardly had sb done when…did…
因为 had done 的动作发生在 从句谓语did 以前,是属于过去的过去,所以用过去完成时.
Hardly had she sat down when the doorbell rang."她刚一坐下门铃就响了."
2.not until ...did sb do 中 did.do 是一般过去时部分倒装句式,其前用did表示过去时态,所以后面用动词原形do.
Not until his father came back did he go to bed last night."昨晚直到他爸爸回来他才上床睡觉".