acknowledgement：
first I appreciate my country who give me a comfortable learning atmosphere,second i want to thanks my supervisor(指导老师）for his help and XXXX during the representation.to my classmate.I want to let them know that:you are my proud of my life.being with your guys is the happiest time I ever had.also I have a word to my gf:thanks for shareing with me all the crying or laughing time.you are so sweet,oh,god,I couldnot help crying at this moment
