"Why you always make cold food for me even in such cold winter?" Lily shouted at her mother at the primary school gate. "I am so sorry babe. I made it only two hours before, but it gets cold too quickly" Her mother apologizes with guilt. Pointing at Lisa, Lily says, "Why Lisa can always eat hot food. Her home is further than ours !"
Words heard by Lisa and her mother, Lisa's mother comes to them and says with smile,"Yes, our home is further then yours, so our food must be made for longer time. But I have a secret weapon. Look! " She raises the lunch bag in her hand. "This is my secret. This lunch bag can keep warm for a long time so that the lunch for Lisa will not get cold."
"Where do you buy it? "