Fill in the blank with the most suitable word.

I _______ pay too much attention to the stories.

didn't

The most suitable word to fill in the blank is didn't.

The sentence is in the past tense, and it is about something that the speaker did not do. The word "didn't" is the most appropriate word to use in this context, as it is the past tense of the verb "to do".

The other options are not as appropriate:

• Hasn't is the present perfect tense of the verb "to do". It would not be accurate to use "hasn't" in this context, as the action of not paying attention to the stories happened in the past.
• Wasn't is the past tense of the verb "to be". It would not be accurate to use "wasn't" in this context, as the sentence is not about the speaker's state of being.
• Haven't is the present perfect tense of the verb "to have". It would not be accurate to use "haven't" in this context, as the action of not paying attention to the stories happened in the past.