近年来，全世界的手机生产厂家都盯着我国，并不余力地宣传，致使我国部分年轻人更换手机的速度超过一年一部，形成了快买快扔的“抛弃型”消费行为。可废弃手机含有铅、镉、汞等多种有害物质，若直接丢弃将严重污染土壤和地下水，这告诉我们：（   ）
①避免盲从，理性消费         ②要适度消费，勤俭节约 
③年轻人可追求时尚，通过消费促进经济发展
④在消费过程中要注意保护环境 

函数$f\left(x\right)=\sin \pi x+\cos \pi x+\left|\sin \pi x-\cos \pi x\right|$对任意的$x\in R$都有$f\left(x_1\right)\le f\left(x\right)\le f\left(x_2\right)$成立，则$\left|x_2-x_1\right|$的最小值为(     )

根据短文内容和所给中文提示, 用单词的正确形式完成以下短文

    Beijing is entering the best travel season﹣"golden autumn". The wind is blowing and the sun ____（照耀）. The colorful city sights make autumn the most popular season to visit Beijing.

    "Beijing is an amazing city!I really want to show the special beauty of this country to my friends in ____（加拿大）. "said a tourist who was ____（忙的）taking photos of the Summer Palace.

    In Beihai Park, two young ____（女士） were recording some ancient ____（石头）bridges with their DV.

    "Before the trip, what I knew about China was all from ____（报纸）and television. Actually, it's much ____（容易的）to travel in China than I thought. ____（在…期间）this trip, I've learnt that China is developing very fast. "the girl with a ____（帽子）named Lily said.

    She also said that her travel plan ____（包括）the Great Wall as well. "People here are friendly. They like communicating with foreigners and this makes my trip more pleasant." said the traveler.