The adverb from the adjective hard is hard.形容词 hard 的副词为 hard：◆I have to work hard today.今天我得努力工作。◆She has thought very hard about her future plans.她曾经苦苦思考将来该怎么办。◆It was raining hard outside.外面雨下得很大。
Hardly is an adverb meaning 'almost not'. * hardly 为副词，意为几乎不、几乎没有：◆I hardly ever go to concerts.我很少去听音乐会。◆I can hardly wait for my birthday.我迫切等待着我的生日。 It cannot be used instead of hard.该词不能代替 hard：◆I've been working hardly today.◆She has thought very hardly about her future plans.◆It was raining hardly outside.
➡ note athardlyhardly / scarcely / barely / no sooner
Hardly, scarcely and barely can all be used to say that something is only just true or possible. They are used with words like any and anyone, with adjectives and verbs, and are often placed between can, could, have, be, etc. and the main part of the verb. * hardly、scarcely 和 barely 均可指刚刚、几乎不，与 any 和 anyone 等词以及形容词和动词连用，常置于 can、could、have、be 等和动词主要成分之间：◆They have sold scarcely any copies of the book.这书他们几乎没卖出几本。◆I barely recognized her.我几乎认不出她了。◆His words were barely audible.他的话勉强听得见。◆I can hardly believe it.我几乎不敢相信。◆I hardly can believe it.
Hardly, scarcely and barely are negative words and should not be used with not or other negatives. * hardly、scarcely 和 barely 为否定词，不应与 not 或其他否定词连用：◆I can't hardly believe it.
You can also use hardly, scarcely and barely to say that one thing happens immediately after another.亦可用 hardly、scarcely 和 barely 表示刚…就…：◆We had hardly/scarcely/barely sat down at the table, when the phone rang.我们刚在桌子旁坐下，电话铃就响了。 In formal, written English, especially in a literary style, these words can be placed at the beginning of the sentence and then the subject and verb are turned around.在正式的书面语中，尤其在文学体中，上述各词可置于句首，然后将主语和动词的位置倒装：◆Hardly/Scarcely had we sat down at the table, when the phone rang.我们刚在桌子旁坐下，电话铃就响了。 Note that you usually use when in these sentences, not than. You can also use before.注意：在这类句子中通常用 when 而非 than，亦可用 before：◆I scarcely had time to ring the bell before the door opened.我刚一按门铃，门就开了。No sooner can be used in the same way, but is always used with than. * no sooner 与上述词用法相同，但总与 than 连用：◆No sooner had we sat down at the table than the phone rang.我们刚在桌子旁坐下，电话铃就响了。
Hardly and scarcely can be used to mean 'almost never', but barely is not used in this way. * hardly 和 scarcely 可表示几乎从不、难得，但 barely 不这样用：◆She hardly (ever) sees her parents these days.这些日子她难得见到她父母。◆She barely sees her parents these days.