There are three forms of adverbs: adverb formed by adding -ly to an adjective, adverb that shares an identical word with an adjective, and adverb not derived from an adjective or any other word.

a) Most adverbs are formed by adding -ly to an adjective. 

Examples:

  • He had a  sudden  heart attack while jogging. (Adjective)
  • He  suddenly  had a heart attack while jogging. (Adverb)
  • She had a  quick  walk to get there on time. (Adjective)
  • She walked quickly  to get there on time. (Adverb)

(See List 8 - Adverbs for more examples.)

Converting a number of adjectives to adverbs by adding -ly entails removing a letter  as shown in the following.

Examples:

  • by adding –ly  or –ally  to the end of an adjective (quick –quickly, heroic –heroically),
  • by adding –ly  after removing the last –e  from an adjective (comfortable–comfortably, possible–possibly), 
  • by dropping the last from an adjective and replacing it with –ily  (easy–easily, happy–happily).

b) Adverbs that share identical words with an adjective.

Some examples of adverbs that have the same form as adjectives and have similar  meanings are:  far fast hard long right straight tight , wrong .

Examples:

  • I got a cheap  pair of shoes in the sale. ( Adjective)
  • I got a pair of shoes  cheap  in the sale. ( Adverb )
  • The workers find the new machine  easy  to operate. ( Adjective )
  • The workers operate the new machine  easily . ( Adverb )
  • Where we live isn't far  from here. ( Adjective )
  • We don't live  far  away from here. ( Adverb )
  • She found the work quite  hard . ( Adjective )
  • She worked quite  hard . ( Adverb )
  • The two brothers live on  opposite  sides of the city. ( Adjective )
  • She has a brother who lives  opposite  to her. ( Adverb )
  • If we exercise regularly, we may live a  longer  life. ( Adjective )
  • If we exercise regularly, we may live  longer . ( Adverb )
  • You have written the  wrong  name. ( Adjective )
  • You have written the name  wrong . ( Adverb )

(See List 9 - Adverbs sharing same words as Adjectives for more examples.)

c) There are adverbs not derived from an adjective or any other word.

Adverbs:  as,even, how, never, next, now, rather, so, soon, still,then, and too.

Examples:

  • He doesn't  even  know where the Pacific Ocean is
  • He said he had never been to a circus.
  • She has got rather a lot of money to spend at this time of the month. .
  • She has eaten two big pizzas and is still  hungry.

There are many adverbs that do not end in –ly. Adverbs (in bold) coming after verbs do not end in –ly.

Examples:

  • The climbers strove  hard  to reach the top.
  • The boy jumped  over  that fence.
  • The train will arrive  soon .
  • You can put this book  up  on the top shelf.
  • Your mother called  yesterday . .

Adverbs are also formed from other parts of speech such as noun (accident), verb (hurry), adjective (bad) and from present participle (frightening). .

Examples:

  • She deleted my file by  accident . (Noun)
  • She  accidentally  deleted my file. (Adverb)
  • Nick  hurried  to answer the telephone. (Verb)
  • Nick moved  hurriedly  to answer the telephone. (Adverb)
  • Excessive smoking is  bad  for the health. (Adjective)
  • His health is  badly  damaged by excessive smoking. (Adverb)
  • He's  frightening  us with the speed he's driving. (Present participle)
  • Frighteningly , there is little we could do with the speed he's driving. (Adverb)