Final answer:
The vague pronoun in the sentence is 'they,' which can be replaced with 'the twins' to clarify that the twins did not want to go home.
Step-by-step explanation:
The sentence “Nigel and Mario took the twins to the park, and they didn't want to go home” contains a vague pronoun, which is 'they'. The vague pronoun in the sentence is 'they,' which can be replaced with 'the twins' to clarify that the twins did not want to go home.
This pronoun is vague because it is unclear whether 'they' refers to Nigel and Mario or to the twins. To make the sentence clearer, you can replace the vague pronoun with the specific subject it refers to. Here is a revised version of the sentence for clarity:
Nigel and Mario took the twins to the park, and the twins didn't want to go home.
This revision removes the ambiguity by specifying that it was 'the twins' who did not want to go home.