hardly 是副词，意思是 "几乎不"；hard 也可是副词，意思是“努力地”：
hardly 位于句首时，句子要用倒装：
hardly 常用于 hardly had...when 结构，翻译为“刚…就…”，表示一件事紧接着一件事发生，与过去完成时连用。when 引导时间状语从句时，主句一般用过去完成时，从句用一般过去时。hardly 置于句首时，助动词 had 要放在主句的主语前。
Hardly had I arrive at the railway station when the train started. 我一到火车站，火车就开走了.
没有 when 时，hardly 翻译为“几乎不”
Hardly had I believe what you said. 我几乎不相信你说的话.
句子中有 hardly 时，其反意疑问句的疑问部分应该用肯定形式：
He can hardly understand it, can he? 几乎听不懂，不是吗?