AcknowledgementsI want to express my sincere gratitude to my supervisor Prof
Zhang Baolai
Without him, I can never finish my thesis
At the beginning of writing this thesis, I had no idea of how to arrange it
Zhang brought me great hope with his constant encouragement and patient guidance, and finally I can have a clear arrangement to my thesis
I also want to say thank you to my dear parents and my younger sister, who accompanied me and cared for me all the time
It’s really an uneasy journey to complete this thesis and they are the one who encouraged me to overcome the pressure and difficulties
My appreciation also goes to my friends, with whom I spent my valuable and wonderful four years
I really learned a lot from them
AbstractAs a well–known humorist and a prolific writer, Mar