Level A1
Adverb formation (-ly)
To say how someone does an action, the describing word gets -ly (slow → slowly, beautiful → beautifully); next to a person or a thing it has no ending. Special: good → well; fast and hard stay the same.
He works slowly.
Look: He works slowly. Slowly tells us how he works.
Forms
He is slow.— slow describes him, the personHe works slowly.— how he works: the word gets -lyIt is a beautiful day.— next to a thing, a day: no ending
A common mistake
Wrong: He works slow.
Right: He works slowly.
So many people say He works slow, but slow describes a person, not an action. We say: He works slowly.
More examples
She sings beautifully.
Long words work the same way: beautiful, beautifully. She sings beautifully.
He works well.
Some words are special: for an action we say well, not good: He works well. And fast and hard stay the same.