Some adverbs have the same form as the corresponding adjective, for example: long, far, little, much, straight, low, fast, hard.
Some adverbs have two forms — one that coincides with the corresponding adjective, and another that ends in -ly. The two forms usually have the same meaning:
The ship arrived safe(ly).
She bought it cheap(ly).
With the following adverbs, the two forms have different meanings:
hard — intensely, very hardly — scarcely
late — late lately — recently
near — near nearly — almost
short — short shortly — soon
pretty — quite prettily — beautifully
Adjective Adverb Adverb with ending -ly
This pencil is hard. She studies hard. He can hardly move.
It was late autumn. She came home late. He has not been well lately.
She is pretty. It is pretty dark. They were prettily dressed.