Unexpeted situations

What do you do when a friends ask you to do something but you have not asked your parents for permission to go there?

First I say not because they did not give me permission and if they want me to go I have to go to my house and ask if they let me.

what do you undestand about an unexpected situation.First you must reason before doing something 

. Did you have an unexpected situation in the school?If when a colleague misses a team work and I have to solve it, or when I forget a task