Voluntary Work on April 16

We visited a couple of old ladies in Nam Cheong Estate, Sham Shiu Po. One of them had 3 granddaughters. Sunny and Anskar organized some indoor games with the 3 girls, which they enjoyed very much. The first game was called "Hangman". The girls had to guess the letters contained in a word that Sunny and Anskar had in mind. Each time they guess wrongly, a part of the "Hangman" is drawn. They should be able to complete the word before the "Hangman" is completed. Otherwise, they would lose. The second game was to give the English translation of some very simple words written in Chinese. The first one to give the correct answer wins the game. The third game was the most exciting one. The girls had to look for the orange which Sunny and Anskar hid inside the house. When they got close to the object we said "Ring, ring, ring". When they walked away from it we said "Bell, bell, bell". It took them awhile to find the orange. Do you know why?