Mistakes in the use of participles and degree modifiers
Incorrect: She had a much shocked expression on her face.
Correct: She had a very shocked expression on her face.
Incorrect: She looked much frightened.
Correct: She looked very frightened.
When a past participle is used as a gradable adjective, it can usually be modified by very. Much cannot be used in this case. Past participles referring to mental states, reactions and feelings are usually used in this way.
Incorrect: That is James, unless I am very mistaken.
Correct: That is James, unless I am much mistaken. OR That is James, unless I am very much mistaken.
Incorrect: She is a very known writer.
Correct: She is a well-known writer.
These are exceptions to the rule given above. Certain past participles like mistaken and known are not used with very.
Incorrect: He is very admired by his followers.
Correct: He is much admired by his followers. OR He is very much admired by his followers.
When a past participle is used as part of a passive verb, we use much or very much to modify it.
Grammar notes
With some adjectives referring to emotional states and reactions (e.g. amused), all of these degree modifiers can be used.
I was very amused by her performance.
I was much amused by her performance.
I was very much amused by her performance.