学位论文使用授权声明　本人完全了解学校有关保留、使用学位论文的规定,同意上海外国语大学保留并向有关　部门或机构送交论文的书面版和电子版,允许论文被查阅和借阅。本人授权上海外国语大学　将本论文的全部或部分内容网上公开或编入有关数据库进行检索,可以采用影印、缩印或扫　描等方式保存和汇编本论文。对于保密论文,按保密的有关规定和程序处理。　学位论文作者签名:　签名日期:　年月日导师签名:　签名日期:　年月日I致谢　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。　所有一级标题均需　用宋体,　三号,　加粗。　宋体　小四　1.5　倍行　距每段段首缩进2个汉字II　摘要　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX。　XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX　XXXXXXXXXXXXXXXXXXX