Adverbs of manner are used to tell how something happens, and answer the question in what way? Adverbs of manner usually come after the object or the main verb.
My sister speaks French well.
I always do my homework quickly.
Adverbs of degree of certainty are used to describe how certain the speaker feels about something, and answer the question how certain? Adverbs of degree of certainty are placed before the main verb unless this verb is ‘to be’.
They surely won’t come.
She is probably at school.
Adverbs of frequency are used to express the frequency of an action, and answer the question how often? Adverbs of frequency come before the main verb but after auxiliary verbs. The exception is the main verb ‘to be’.
She often goes to the cinema alone.
You can always tell me about your problems.
He is never late.
There are adverbs with the same form as adjectives: hard, fast, loud, only, high, early.
I swim fast. (‘fast’ – adverb);
I’m a fast swimmer. (‘fast’ – adjective)
There are also adverbs with two forms. One form looks like the adjective, and the other form has -ly ending.
The music sounds loud.
The music sounds loudly.
Sometimes two forms of the adverb have different meanings.
I came too late. (‘late’ means ‘not early’)
I haven’t visit them lately. (‘lately’ means ‘recently’)