The incorrect pronoun shift in the sentence is found in the use of "their," since it is a plural pronoun referring to the singular word "someone," seen below.
<h3>What is a pronoun shift?</h3>
A pronoun shift is a change in the use of pronouns. We have an incorrect pronoun shift when the pronoun does not correctly refer back to the word it is replacing.
That is the case in the sentence we are analyzing here. The word "someone" is singular. Therefore, if we are to use a pronoun or another word to refer to it, it should also be singular. However, the possessive adjective "their" is plural, which means its use is incorrect.
To correct the sentence, we could do the following:
- Someone left his or her backpack in the library.
Learn more about pronoun shift here:
brainly.com/question/24463058
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