Dear to whom it may concern,
Would you please explain to me that What is the difference between[color=red] hard and [color=red]hardly when we use in adverb?
Regards
Mitra584 
The difference can be summed up in this joke:
Working hard or hardly working?
To work hard = to really apply yourself
To hardly work = to do almost no work, to go through the motions.
My dear I know Bees must have been the one to teach but I will try:
HARD is an adjective because it describes a noun so you can say: Dont cut that hard tree. This is a hard fruit. The glass is hard. So it is alway there to talk about a noun, as you can form examples with yourself.
HARDLY is an adverb because it always qualifies verbs, nouns and as well some adverbs for instance
:
It is hardly to hear.
I can easily beat you. Remember that almost all adverbs end with the letter ‘y’ like, badly, soundly.
I’m afraid your rule doesn’t quite work.
“Hard” is an adverb, and yet it doesn’t end in a “y”.
There are many others that don’t adhere to this rule (sound, fast, aback, asunder to name a few).
“hard” can be an adjective or an adverb. It is an adjective in “This is a hard fruit” for example, but an adverb in “to work hard”.
I find this note to be very useful ( oald8.oxfordlearnersdictionaries … ary/hard_2 ):
The adverb from the adjective hard is hard:
I have to work hard today. ◇ She has thought very hard about her future plans. ◇ It was raining hard outside.
Hardly is an adverb meaning “almost not”:
I hardly ever go to concerts. ◇ I can hardly wait for my birthday.
It cannot be used instead of hard: I’ve been working hardly today. ◇ She has thought very hardly about her future plans. ◇ It was raining hardly outside.