Such is sons' nature，I really do not know how to express my thanks to you. However，I can imagine，on the day 18 years ago，when you gave birth to me，what a complex feeling you had. In the past few years，every day you struggle me up in the morning and prepare breakfast for me，then in the afternoon，you always welcome your only son with delicious foods after a day’s hardwork. Now your son has been 18 and will go to university soon，like a bird is leaving its parents. Nevertheless，your footprints on my heart will never ever fade and——I love you mum!