Acknowledgements First and foremost, I would like to show my deepest gratitude to mysupervisor, Dr. Liu Shaolong, a respectable, responsible and resourceful scholar,who has provided me with valuable guidance in every stage of the writing of thisthesis. Without his enlightening instruction, impressive kindness and patience, Icould not have completed my thesis. His keen and vigorous academic observationenlightens me not only in this thesis but also in my future shall extend my thanks to Mrs. Liu for all her kindness and help. I wouldalso like to thank all my teachers who have helped me to develop the fundamentaland essential academic competence. My sincere appreciation also goes to theteachers and students from No. 16 Senior Middle School and GuangdongUniversity of Foreign Studies, who participated this study with great cooperation. Last but not least, I' d like to thank all my friends, especially my three lovely roommates, for their encouragement and support.