One possible version：

Dear Anderson,

From TV I know there are still many H7N9 flu cases reported in Shanghai and some people are even killed as a result .I’m so worried about you .So I am writing to get to know some information about you .Are you all right ?Are there any H7N9 flu cases in your school ?Are you still afraid of this widespread sisease ?

To stay away from the disease , I strongly suggest you doing the following things .Firstly , you’d better stay at home as much as possible and not go to places where there are many people .Then it would be a good idea to wash your hands more often to keep them clean .Besides , open the window to have more fresh air in the room.And last but not least , eat more fruits and vegetables to keep yourself fit and strong.

So far the disease is not so deadly as it seems to be .Do be at ease! Take care and you’ll be ok.

Yours ,

LiHua

题目分析：本文要求写一封书信，学生们对书信这种题材比较熟悉，而且格式已经给出，只需根据要求把要点表达清楚即可。书信内容一般首先提出写信的目的，就本文而言应该先写出目前H7N9存在的情况以及对朋友健康和安全的担心，然后再提出防护意见。在提建议的时候应该按照要求至少给出三点建议，为了使文章层次清晰应该使用一些表示顺序的连词，如：first、second、third；或者besides、moreover、what’s more等。此外，在写作时还有尽量使用多种句式，比如状语从句、定语从句和强调句型等，以增添文章的亮点。

【亮点说明】本篇范文层次清晰，要点全面。开门见山提出了写信的目的，而且连续用了三个疑问句来询问朋友及他周围的情况，表达了作者深切的关爱之情。在表述建议时，作者用了firstly、then、besides和last bur not least等词语有效地起到了连接作用，不仅显得段落层次清晰，而且使文章结构紧凑，语义连贯。在本文中作者多使用了简单句和一些短语，如To stay away from the disease，last but not least等 ,使文章语言简洁流畅,读起来朗朗上口。