阅读下面短文，完成相应的任务。
Dear Sir，
I'm a student in Grade 8. My name is Li Hua and I'm 14 years old. I'm writing to recommend myself as a volunteer to share Chinese culture through stories.
I really like reading and have read lots of classics on Chinese history，so I'm familiar with Chinese culture. And I have a good command of English. Therefore，it's not difficult for me to tell traditional folk stories in English. What's more，I have much experience in communicating with foreigners.
For me，this volunteer work can not only increase my interest in learning English but also improve my understanding of Chinese culture. As a Chinese student，it's my duty to make more people know about our history and culture! Sincerely hope you can give me this chance and I'm looking forward to your reply.
Yours，
Li Hua
任务：回答以下问题。
1. 第三段中，李华阐述了做志愿者的意义，他用了哪个短语将两种意义整合到了一句话里？

2. 斜体词“Sincerely”有何作用？

四、1. not only... but also...
2. 能使期待更显真诚，符合申请信的语言得体性。

【解析】
1. 定位到第三段第一句，李华使用“not only... but also...”这个短语，将“增加英语学习兴趣”与“加深对中国文化的理解”这两个做志愿者的意义整合到同一句话中。
2. “Sincerely”是英文书信里的礼貌用语，用于修饰“hope”，能让表达的期待更显真诚，契合申请类书信语言得体的要求。
【答案】
1. not only... but also...
2. 能使期待更显真诚，符合申请信的语言得体性。
【知识点】
并列连接短语运用、英文书信礼仪
【点评】
本题考查学生对文本细节的捕捉能力以及英文书信的语用知识，要求学生既要精准定位文本信息，又要掌握书信写作的得体表达。
【难度系数】
0.7