答案：C

题目分析：考查倒装句，Hardly +had sb done…when…，“一…就…”,如果用No sooner had sb done 应该和than搭配，句意：我一上火车，火车就开了。选C。

点评：在以never, little, hardly, not only, few, not, seldom等否定副词开头的句子中，采用部分倒装。如不放在句首就不要倒装。Hardly…when…,no sooner…than…就属于这种用法。