One possible version:

Dear Sir/ Madam,

I am a Chinese student who is going to study in London next month. I ‘m writing to ask you for finding a host family for me. Here are my requests.

First, I’d like a room of my own, which is clean and comfortable. Second, the apartment should not be far away from the center of the city. That is to say, it is convenient for me to get around. Third, the family can speak fluent English. In addition, I’d appreciate it if the host family can provide a washing machine and some cookers without additional charges so that I am able to wash my clothes and cook my own meals.

Looking forward to your early reply.

Yours

Li Hua

试题分析：本文是篇材料作文，材料非常简单，学生很容易把握写作要求和写作目的。考生在写作之前必须认真审题， 要求让你写一封信说明对寄宿家庭的要求，对房子的位置和地段以及房间的要求和房东类型都需要以第三人称来说明。时态是一般现在时即可。还有就是应该注意句子的衔接和高级词汇的应用，以提高作文的档次。

【亮点说明】文章结构清楚，有条理，并使用了非常好的词语和句子为文章增色不少，比如 additional charges，It is convenient for… to do sth.; I’d appreciate it if …,以及which引导的非限制性定语从句等等。并注意了句子的衔接如：That is to say，In addition等等。值得学习借鉴。