Answer:
The sentences that correct the vague pronoun problem are:
The police officer chased the criminal through the streets until the officer tripped and fell.
The police officer chased the criminal through the streets until the criminal tripped and fell.
Explanation:
In the original sentence, "The police officer chased the criminal through the streets until he tripped and fell", we have the following information:
- There was a police officer;
- There was a criminal;
- The officer chased the criminal;
- One of them tripped and fell.
Because the speaker of the sentence used the pronoun "he" when there are two possible third-person singular nouns for it to be substituting - officer and criminal -, "he" ends up being vague. We do not know who it refers to.
Thus, the best way to correct this problem is by choosing one of the nouns to be the one who tripped and fell, and using it instead of the pronoun "he".
- The police officer chased the criminal through the streets until the officer tripped and fell.
- The police officer chased the criminal through the streets until the criminal tripped and fell.