Final answer:
The incorrect sentence is 'She excepted the proposal.' It should be 'She accepted the proposal.' 'Accept' is to agree or receive, while 'except' means to exclude.
Step-by-step explanation:
The sentence that uses the words 'accept' or 'except' incorrectly is: She excepted the proposal. The correct usage should be 'She accepted the proposal' as the verb 'accept' means to receive something willingly, while 'except' generally functions as a preposition meaning 'excluding'. The correct usage of 'accept' is shown in sentences 1 and 3, where the verb is used to indicate agreement or reception. Sentence 4 correctly uses 'except' to denote exclusion.