Shopping for mom 3

Brother:  Why is it so important that I take you to the mall. Sister:  Because tomorrow is mom's birthday, and  I have to go to the mall to buy her a birthday present. Brother:  Oh, in that case I guess I need to go to the mall today. Sister:  What? You forgot that tomorrow is mom's birthday! Brother:  No I didn't! Sister:  Yes you did! Brother:  No, I didn't, I just haven't had any time. I have been very busy lately. Sister:  No you haven't! You have been playing  video games all week long. Brother:  Well, I have been busy playing video games. Anyway, let's just hurry up and go to the mall.