Much is a noun that is used to refer to a large amount or quantity of something, usually to emphasize the size.
1. 'There's much to be gained by living a healthy lifestyle.'
2. 'She gave away much to become the best.'
Much should not be used before a plural noun or with comparatives or superlatives. For example, incorrect usage would be
'He bought much toys.' or 'There's much best place to go.' Instead, use the determiner 'many', for the former sentence and 'the best' in the latter.
Much is used as an adjective to describe an overwhelming amount of something.
1. 'He had much trouble understanding the instructions.'
2. 'There's much at stake in this election.'
3. 'She had much difficulty convincing her parents to let her attend the party.'
Much should not be used after the verb 'to be', as in the sentence 'The exam was much difficult'. Instead, use the comparative or superlative forms of the adjective, such as 'more difficult' or 'the most difficult'.
Much is used as an adverb to describe an activity or action done to an overwhelming degree.
1. 'She worked much harder than her colleagues.'
2. 'He talked much faster than anyone else in the room.'
3. 'She laughed much louder than anyone else.'
Much should not be used with other adverbs (such as 'very') or adjectives. For example, incorrect usage would be
'She ran much very fast.' Instead, use 'very much' when modifying an adjective or adverb.