假设你在2009年3月28日参加了“地球一小时（Earth Hour）”活动，请你在校园网的BBS论坛中用英语介绍这一活动并发表感想。
[写作内容]
请根据以下表格内容，写一篇短文。
| 名称 | 地球一小时（Earth Hour） |
| 时间 | 每年3月最后一个星期六，当地时间晚上8.30~9.30 |
| 形式 | 熄灯一小时 |
| 目的 | 提高环保意识，应对气候变化 |
| 发展 | 2007年始于悉尼，之后迅速发展 |
| 2009年约90个国家4000多个城市10亿（one billion）参加 | |
| 感想 | …… |
[写作要求]
（1）只能使用5个句子表达全部内容；
（2）文中不能出现真实姓名和学校名称。
[评分标准]
句子结构准确，信息内容完整，篇章结构连连贯。
Earth Hour, an annual international event held on the last Saturday of March, asks people to turn off their lights from 8.30 to 9.30 pm of the local time. Its purpose is to raise people’s awareness of the environmental protection and the climate change. Earth Hour first began in Sydney in 2007 and after that, it spread around the world at an amazing speed. This year, more than 4.000 cities from 90 countries and some one billion people from around the world have joined Earth Hour. Though it is a single mass event, people are contributing in their own way to saving our planet and one hour’s going dark means a bright future.