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The sentence that contains an unclear antecedent is "they say that doing homework leads to his success in school."
In grammar, an antecedent is an expression that a pronoun refers to. In other words, an antecedent tells us who or what the pronoun is referring to or based on.
- In the given sentences, the antecedents are clearly included except in sentence D.
- Sentence D has the pronouns "they" and "his" but we are not given any indication of who "they" or "his" refer to.
- In this case, there is no antecedent for the two pronouns used, thereby making it unclear.
An antecedent is supposed to clarify the pronoun used in a sentence. So, among the given sentences, sentence D does not contain any clear antecedent.
Learn more about antecedent here:
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