已知甲乙两组数据的平均数都是5，甲组数据的方差S_甲²=2.1 ，乙组数据的方差S_乙²=1.2 ，则(      )

和静脉血相比，动脉血（　　）

下列语段中的空缺处语序排列正确的一项是（4分）
太阳已经下山了，___________________，明明还在前边不远处的人，拐个弯儿就不见了，吓得我赶快跑了几步，生怕被丢下。
①脚下细细的小路淹没在草丛里②树木茂盛的枝叶挡住了视线③一颗星星不甘寂寞地闪着微光④仿佛在招呼同伴们早早出来布置天幕⑤天边最后的一点霞光正在被黑夜慢慢吞噬⑥夜虫也开始轻声鸣叫，演奏起黄昏圆舞曲

下列结论正确的是（   ）

①粒子半径：K⁺＞Al³⁺＞S^2﹣＞Cl^﹣

②氢化物的稳定性：HF＞HCl＞H₂S＞PH₃＞SiH₄

③离子的还原性：S^2﹣＞Cl^﹣＞Br^﹣＞I^﹣

④氧化性：Cl₂＞S＞Se＞Te

⑤酸性：H₂SO₄＞H₃PO₄＞H₂CO₃＞HClO      

⑥非金属性：O＞N＞P＞Si

⑦金属性：Be＜Mg＜Ca＜K．

阅读理解

    It was on the early afternoon of a mid­October day in 2012. Bismark Mensah, who came to America several months ago, was collecting carts (手推车) outside a Walmart in Federal Way. It was a part­time job for him. He earned $9.05 an hour in charge of getting carts out of the parking lot.

    He was used to finding stuff in carts that customers had somehow forgotten—keys, credit cards, wallets. And he turned them into a customer service. But a particular item stood out. It was a white envelope with a clear window in the middle, and there was a lot of cash in it, around $20,000. Mensah turned them into customer services.

    Because of what he did that afternoon, Mensah is now the winner of Walmart's national 2013 “Integrity(正直) in Action Award”．

    Bismark Mensah says that since the story ran, he has become the model the youth in Ghana (his native country)．

    He is now employed full­time at the Federal Way Walmart, earning $10.95 an hour, up from the $9.05 an hour he earned working part­time.

    Mensah, 33, no longer collects carts and such. He is in the backroom, dealing with inventory(库存). “I want to learn everything about operating a store like Walmart store，” he says. He plans to return to Ghana to run some shops owned by his family. He also plans to go to college and earn a degree in business administration.