Are you ready for adventure (冒险)? Then Sunny Shores Sea Camp is the place for you! The activities there are all about the sea.
At Sunny Shores Sea Camp, you can get excited and improve your skill-level. You can enjoy the wonders of Sunny Island. From diving（潜水）to sailing, sea science to seafood, Sunny Shores Sea Camp offers courses for your different interest. You can also learn about the sea environments of Sunny Island. It is hard for you to find anywhere else like that.
    Whether you're a beginner or already an expert (专家), Sunny Shores Sea Camp is a great place that brings together campers from all over the world.
    Wonderful memories and new friends are waiting for you at Sunny Shores Sea Camp!
Camp Activities: Adventure . Sea Biology. Diving . Sailing . Windsurfing
Camp Address: Sun Bay , South Florida 000634
Dates: June 28 - July 18 , July 21 -August 9
Cost Week: $600 - $900
Campers Ages: From 13 to 17
Contact us: Sign up at www.sunnyshoresseacamp.org! Or call 800-645-14231

科学家最新研究表明，吸烟会导致人的寿命减少，按天计算，平均每天吸一包烟可以导致寿命减少2小时20分，如果一个人一个月有n天每天吸一包烟，则这个月他的寿命减少了____ 天．

下列变化中，属于化学变化的是（   ）

建立宏观、微观和符号之间的联系是学习化学的重要方法．请按要求填空．

（1）碳酸钠是一种重要的化工原料，其化学式为　____ ；

（2）恩施被誉为世界硒都，具有丰富的硒资源．硒（Se）是人生命中必需的微量元素，在周期表中与硫同族、化学性质相似．A、B、C、D表示4种物质，它们的微观示意图如图：

物质A和B在点燃条件下反应生成C和D两种物质，反应的化学方程式是____ ，其基本反应类型是____ ．

（3）有机化学中的最简式﹣用元素符号表示化合物分子中各元素的原子个数最简比的式子．某有机物中C、H、Ｏ元素的质量比为6：1：8，则该有机物的最简式为____ 　（按C、H、Ｏ顺序）．