我区正在全力创建全国文明城区。假如你是李华，你打算邀请你们班交换生Peter参加下周日学校组织的志愿活动。请用英语写一封邀请函，告诉他活动的时间和地点，活动内容以及需要做什么准备。

提示词语： Muhu Park, pick up, water, put up posters, gloves, shoes 

提示问题：When and where will you go?

What will you do in this activity?

What do you advise Peter to prepare for this activity?

Dear Peter,

    How is it going?

    I'm writing to invite you to take part in the volunteer activity.

    I'm looking forward to your early reply.

Li Hua