Question

why did Nicola frown at Jacopo ? why?

Answer 1

Because Nicola was a very self-respecting boy who didn't like asking for help or sharing his problems to anyone specially strangers. So he 'glared' at his brother Jacopo when he asked the narrator to drop them to Poleta.

Answer 2

nicola frown at jacpo because when jacpo asked the narrator if he could drop them at poleta. nicola is a self dignified person and she does not want someone to interfere in hre life.