珠江三角洲地区是我国主要的工业基地之一。

化学用语是化学学科的专用语言，是我们学习化学的重要工具。请你从给定化合价的五种元素中，选择适当的元素，按要求写出相应物质的化学式(每空只填一种物质)：单质  ____ ；金属氧化物____ ；可作为复合肥料的盐____  。

    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

用方框中所给单词的适当形式填空，每词限用一次。

国务院发布的《大气污染防治行动计划》指出，京津冀、长三角、珠三角区域要完成区域、省、市级重污染天气监测预警系统建设，实现多省份跨区域联合治理雾霾。跨区域联合治理雾霾的方法体现了（    ）