Adjective or Adverb?

An adjective describes a person or thing (a careful driver). An adverb describes how someone does something (He drives carefully). It can also go in front of an adjective: completely empty, really good.

• Most adverbs add -ly: slow → slowly, beautiful → beautifully. Consonant + -y becomes -ily (easy → easily), and -le becomes -ly (gentle → gently).
• The adverb of good is well: She speaks English well.
• hard, fast and late stay the same: She works hard. Hardly means "almost not", so it is a different word.
• After be, look, feel, smell, taste and sound, use the adjective, because it describes the subject: You look happy. The soup tastes delicious. That sounds good.