A : Hi, good morning. We have an assignment in Mathematics, have you finished ?
B : Good morning. Oh God ! I'm forget. Thanks so much for remind. Fortunately, i bring my cellphone, so i can use the cellphone's calculator to make the process easier.
A : Hey, our school rules, prohibited students to bring the cellphone, don't we ?
B : But i think, cellphone is useful even in school. We have to use cellphone to call our parents to take us home. Agree ?
A : Yeah. It's a great opinion. But why our school made a rule like that ?