They tell us 'how' something is happening, has happened or will happen.

For example, read this sentence:

The man runs.

We don't know much.

There is a man.

He runs. ('to run' is a verb)

Now read this sentence:

The man runs quickly.

Now we know something about the way he runs (how he runs).
The word QUICKLY is an adverb.

Many English adverbs, but not all, end with the letters 'LY'. This is one of the clues telling us that the word is an adverb and is describing a verb or another adverb.

Now try this sentence:

The man runs very quickly.

Now we know even more about the man's running.
The word VERY is an adverb describing (modifying) the adverb QUICKLY which is modifying the verb TO RUN.

ALWAYS It happens constantly, forever continually, permanently, continuously. It's a sure bet!

FOR EXAMPLE: I WILL ALWAYS LOVE YOU!

ALMOST ALWAYS: It happens not all the time, but close to it. Bet on it!

FOR EXAMPLE: I WILL ALMOST ALWAYS BE AT THE MOVIES ON FRIDAYS.

USUALLY: It happens most of the time, you can expect it.

FOR EXAMPLE: I WILL USUALLY DRINK COFFEE IN THE MORNING.

GENERALLY: It happens most of the time.

FOR EXAMPLE: I GENERALLY FEEL GOOD AFTER A SHOWER.

OFTEN: It happens a lot.

FOR EXAMPLE: I WILL OFTEN WORK OUT ON TUESDAY NIGHTS.

FREQUENTLY: It happens a lot.

FOR EXAMPLE: I WILL FREQUENTLY WORK OUT ON TUESDAY NIGHTS.

REGULARLY: It happens like clockwork; (for example, every hour on the hour)

FOR EXAMPLE: I WILL REGULARLY GO TO WORK ON TUEDAYS.

COMMONLY: It happens. You can find it easily.

FOR EXAMPLE: I COMMONLY SEE DEER ON THE ROAD AT NIGHT.

SOMETIMES: It happens at times but DEFINITELY NOT all the time

FOR EXAMPLE: I SOMETIMES SEE A FOX ON THE ROAD AT NIGHT.

OCCASIONALLY: It happens from time to time, but NOT frequently

FOR EXAMPLE: I OCCASIONALLY SEE AN EAGLE IN THE AIR.

SELDOM: It does not happen often, it happens infrequently

FOR EXAMPLE: I SELDOM SEE A FOX ON THE ROAD IN DAYLIGHT.

RARELY: It does not happen often, it happens infrequently "Once in a blue moon."

FOR EXAMPLE: I RARELY SEE A FOX ON THE ROAD IN DAYLIGHT.

HARDLY EVER: It is not likely to happen. Do not expect it to happen.

FOR EXAMPLE: I HARDLY EVER SEE ELEPHANTS, EXCEPT IN THE ZOO.

ALMOST NEVER: It is not likely to happen. Do not expect it to happen.

FOR EXAMPLE: I ALMOST NEVER SEE MY COUSIN LARRY.

NEVER: It never happens, not at all, not even once

FOR EXAMPLE: I NEVER SEE MY COUSIN STEVE ANY MORE.

MOST Mainly, largely, on the whole

FOR EXAMPLE: MOST OF THE TIME I AM WORKING OR AT SCHOOL.

MUCH A lot, to a great extent, to a large extent

FOR EXAMPLE: MOST OF THE TIME I AM WORKING OR AT SCHOOL.

TOO And, also, besides, as well, in addition, additionally, furthermore, moreover, plus, overly, exceedingly, extremely, excessively

FOR EXAMPLE: MOST OF THE TIME HE IS WORKING TOO.

FOR EXAMPLE: HE IS WORKING TOO MUCH.

VERY Extremely, exceptionally, especially, exceedingly

FOR EXAMPLE: HE IS WORKING VERY HARD TO SAVE MONEY FOR A CAR.

A. COMPARISON: 'LY' ADVERBS

For ALL adverbs that end in 'LY', simply use the word 'MORE' in front of the adverb to form the comparison:

Adverb: Quickly The best student finished the test quickly.
Comparative: More quickly The best student finished the test more quickly than the worst student.

Adverb: Slowly She walks slowly.
Comparative: More slowly She walks more slowly than he does.

Adverb: Carefully Please watch the show carefully.
Comparative: More carefully The more carefully you watch, the more you will see.

Adverb: Happily I will happily meet you for lunch.
Comparative: More happily I would more happily meet you for dinner.

B. COMPARISON: ONE-SYLLABLE ADVERBS ('ER' ADVERBS)

For one-syllable adverbs, simply add the letters 'ER' to form the comparative:

C. IRREGULAR ADVERBS

For all two-syllable adverbs, simply use the word 'MORE' in front of the adverb to form the comparison:

To form the superlative for all adverbs ending in 'LY', simply put the words 'MOST' in front of the adverb.

Adverb: Quickly The best student finished the test quickly.
Comparative: More quickly The best student finished the test more quickly than the worst student.
Superlative: Most quickly The teacher finished most quickly.

Adverb: Slowly She walks slowly.
Comparative: More slowly She walks more slowly than he does.
Superlative: Most slowly The child walked most slowly.

Adverb: Carefully Please watch the show carefully.
Comparative: More carefully The more carefully you watch, the more you will see.
Superlative: Most carefully Whoever watches most carefully will see all there is to see.

Adverb: Happily I will happily meet you for lunch.
Comparative: More happily I would more happily meet you for dinner.
Superlative: Most happily I would most happily live with you.

For one-syllable adverbs, simply add the letters 'ER' to form the comparative:

Adverb: hard He worked hard to finish the job.
Comparative: harder She worked even harder than he did.
Superlative: hardest Her sister worked the hardest of all.

Adverb: fast He worked fast to complete his assignment.
Comparative: faster She worked faster than he did.
Superlative: fastest Her brother was the fastest worker.

C. IRREGULAR ADVERBS

For all two-syllable adverbs, simply use the word 'MORE' in front of the adverb to form the comparison:

SPECIAL NOTE: some English words can be used as an adjective or an adverb, such as FAST:

He is a fast runner. FAST is an ADJECTIVE.

Fast describes the quality of the runner (a noun).

He is a faster runner. FASTER is still an ADJECTIVE (comparative).

Faster compares the quality of the runner as compared to other runners.

He is the fastest runner. FASTEST is still an ADJECTIVE (superlative).

Fastest characterizes the quality of the runner (a noun).

He runs fast. FAST is an ADVERB.

Fast tells about running (a verb), not about the man (a noun).

He runs faster than she does. FASTER is an ADVERB (comparative).

Faster compares the action verb 'to run'.

He runs fastest of all. FAST is still an ADVERB (superlative).

Fastest characterizes the verb 'to run'.