保护生物多样性最为有效的措施是  （   ）

3-2=1，

8+7-6-5=4，

15+14+13-12-11-10=9，

24+23+22+21-20-19-18-17=16，

…

根据以上规律可知，第20行左起第一个数是（    ）

    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

给下列句子加上标点。

①这正是前几天那片千万朵小花藏身的草地____  此刻那些花儿一下子全冒了出来____  顿时改天换地____ 

②我惊奇地想____  它们为什么不是在温暖的阳光下冒出来____  偏偏在冷风冷雨中拔地而起呢____ 小小的花儿居然有如此的气魄____  我的心怦然一震____  这一震____  使我明白了生命的意味是什么____ 是——勇气​ ____