During the process of fulfilling my graduation paper, I have owned my debts to
many people. First and most of all, I would like to express my gratitude to Ms.
Nguyen Thi Huyen, M.A, my supervisor, for her guidance, great suggestions
and advice in each step of the study. Without her precious comments, academic
instructions and wholehearted help, my research would have never been
accomplished.
Also, my sincere thanks are extended to all teachers in Foreign Language
department, Hai Phong Private University for their useful lectures and
suggestions.