【正确答案】Dear John,
Thank you very much for asking me! As we all know, the aged people who live alone are in need of our help, and I'm quite willing and happy to help them as a volunteer. I quite appreciate your Hndness and it must be a great pleasure to participate in this volunteer work.
I am also writing to ask about the detailed things for the work. I need to make sure about the necessary things I should get prepared so I can make preparations ahead of time. Besides, would you please to tell me the exact time and location of the work?
Thank you again for asking me to participate. I am looking forward to your, further reply.
Yours Sincerely，
Wang Lin

【答案解析】[写作点金] 本文属应用文文体，是对朋友邀请函的回复函。首先应该注意回复函的格式。其次要注意正文部分的写作层次：文章的开头就要说明写信人对对方的感谢之情以及明确说明接受邀请，然后要注意写信人需要从邀请者那里获得更多的信息，所以语言要诚恳，尽量使用简短的句式把意思表达清楚。最后要注意再次感谢收信人的邀请，并表明希望尽早得到回复。
[高频词句]
a great pleasure to do sth.很高兴做某事
make sure about sth.确认/证实某事
get prepared做准备
ahead of time提前
I am looking forward to your further reply．期待您的进一步回复！