問題詳情：
假定你是李華，請給正在你校學習的英語交換生Bob寫封郵件，通知他週末有義工活動，詢問他是否參加。主要內容包括：
1.主題：撿垃圾；
2.時間地點；
3.注意事項。
注意：
1. 詞數100左右；
2. 可以適當增加細節，以使行文連貫。
Dear Bob,
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Yours,
Li Hua
【回答】
Dear Bob,
I am writing to inform you that a voluntary activity is to be held this Sunday.
As you know, the litter dropped around has affected the image of the city, so we are scheduled to collect and classify rubbish in Renmin Park. I know you have a strong sense of social commitment and have always involved yourself in voluntary activities. If you have intention to join us, we can meet at the school gate at 9:00 a.m. This activity will last (for) two hours. If you are willing to come, you'd better take gloves with you in case you might get hurt. After all, safety goes first. Comfortable sneakers are also highly recommended.
Looking forward to your reply.
Yours,
Li Hua
知識點：提綱作文
題型：書面表達
