You are waiting for your school bus, but it doesn't show up. What do you do?
Tell my parents to call the driver.
You are in a math lesson and you having trouble understanding the topic. What do you do?
Raise your hand. Ask the teacher to re-explain the lesson.
You are on the train and you look up and see you've gone past your stop. What do you do?
Get off at next stop and switch to train going in the other direction on the line.