Answer:
Sentence 1: 'you' to 'they'
Sentence 2: 'me' to 'I'
Sentence 3: 'they' to 'h/she'
Sentence 4: 'test' to 'it'.
Explanation:
Pronouns are described as the words that replace or substitute a noun or a noun phrase in a sentence. It serves either as a subject or as an object in the sentence that enhances the readability of the sentence by preventing a repetition of a noun. As per the question;
Sentence 1 needs correction as the collective noun 'people' requires a pronoun equivalent to it and thus, 'they' should replace 'you'.
Sentence 2 wrongly employs 'me' which is used in an object's position and since conjunction 'and' carries two equivalent forms so, 'I' must substitute 'me'.
In sentence 3, the indefinite pronoun 'someone'(denotes singular) must be replaced with a singular pronoun. Thus, 'he or she' would replace 'they' in the sentence.
Sentence 4 employs 'it' without mentioning the noun. Therefore, 'test or exam' would replace 'it'.