依次填入下面一段文字横线处的语句，衔接最恰当的一项是(　　)

令科学家感到担忧的是，凡·高、塞尚和其他画家的数十幅名作可能因为博物馆和画廊的LED灯光而存在遭受不可逆转的破坏的风险。           ，           。           ，           。           ，           。

①但最新的研究发现，受到凡·高和塞尚等画家追捧的黄色颜料有一大弊端

②黄色颜料中富含的铬酸铅在灯光照射下易变色

③长期以来，LED灯被视为保护这些画作的最理想方式

④也提醒博物馆应认真对待基于LED灯的照明系统可能产生的影响

⑤因为这种灯能够避免自然光和其他灯光对画作造成破坏

⑥这一研究发现，让绘画作品保护者陷入深深忧虑之中

某校八年级四班仿照中央电视台《朗读者》节目开展语文综合性学习活动，请你参（1）加。

【认识《朗读者》】

       伶熙紫杉：所有的选择都不如徐静蕾的一颗《奶奶的星星》——她结合自己的故事，为去世多年的奶奶朗诵作家史铁生的经典散文《奶奶的星星》,字字入心，几度哽咽，瞬间戳中万千心灵……

       panyue1997：《朗读者》这个大型文化情感类节目很好，每个朗读者的背后都有一段动人心弦的故事，每一个故事都令我泪流满面。

       kid．666：虽然没有受过专业的训练，不懂什么朗读技巧，但是他们那蕴含着感情的声音却不停地撞击着我的心灵。

有一宇宙飞船到了某行星上(该行星没有自转运动)，以速度v接近行星赤道表面匀速飞行，测出运动的周期为T，已知万有引力常量为G，则以下说法错误的是 (　　)

硫酸亚铁铵的化学式为（NH₄）₂SO₄•FeSO₄•6H₂O，是浅绿色晶体，商品名为莫尔盐，易溶于水，不溶于乙醇．

完成下面的实验报告：

【实验原理】

【实验用品】

10%Na₂CO₃溶液、Fe屑、3mol/LH₂SO₄、（NH₄）₂SO₄固体、蒸馏水、无水乙醇．锥形瓶、蒸发皿、酒精灯、玻璃棒、烧杯、铁架台、漏斗、托盘天平、量筒、滤纸．

【实验步骤】

（1）Fe屑的处理和称量

称取3g铁屑，放入锥形瓶，用10%Na₂CO₃溶液，除去Fe屑表面的油污，将剩余的碱液倒掉，用蒸馏水把Fe冲洗干净，干燥后称其质量m₁g．

（2）FeSO₄的制备

将称量好的Fe屑放人锥形瓶中，加入15mL 3mol/LH₂SO₄，加热10min后（有氢气生成，用明火加热注意安全）．　      a      　，并用少量热水洗涤锥形瓶及滤纸，将滤液和洗涤液一起转移至蒸发皿中．将滤纸上的固体干燥后称得质量为m₂g．

①a处的操作是____ ；

②制取FeSO₄时，加入的Fe为什么要过量？（用离子方程式表示）____ 　

（3）（NH₄）₂SO₄•FeSO₄•6H₂O的制备

根据FeSO₄的物质的量，计算并称取（NH₄）₂SO₄固体，并将其加入上面实验的蒸发皿中，缓缓加热，浓缩至表面出现结晶薄膜为止．____ ，得到硫酸亚铁铵的晶体．过滤后用无水乙醇洗涤晶体，除去其表面的水分，称量得到的晶体质量为m₃g．

①b处的操作是____ ；②制备莫尔盐晶体时，为什么不能将溶液蒸发至干？____

（4）产品检验

微量Fe³⁺的分析．称0.5g产品置于25mL比色管中，加水溶解后加1mL 25%的KSCN溶液，继续加水至25mL刻度，摇匀，与教师所给标准对比，评价产品质量．写出该过程所发生反应的离子方程式：____ 

【实验记录】

    It's a small gas station that has snacks, drinks, cigarettes, and candies. The young man behind the counter knows his 1by name and what they usually want to buy. He treats children and adults with equal2He reads science fiction behind the counter when business is3

    One day, three people rushed in and grabbed food off the shelves as fast as they could,4not planning to pay for it. He hit the “panic button”, then went over the counter and 5the front door. It was obvious they were homeless, and equally obvious that they weren't going6with the food. They7the food and simply crowded together in panic— knowing the police were8 the way.

    Imagine what they must have felt like when they were told they didn't have to steal if they were that9“We have food in the back, expired (到期) but still 10to eat. If you need food, you11have some.”

    They were told to12what they had dropped and put it back, and then asked to sort out the mess. They were doing just that13the police arrived. The officers were told the situation was under control and the police were no longer14.

    This wasn't what they had 15.They were being treated as human beings who could right the wrong they'd done. Shocked, they quickly followed orders to take turns and use the restroom to clean up themselves.

    Soon three 16people walked out with all the17their arms could hold. They were18that, if they needed to come back again, they were to ask and not just grab.

    And then the young man went back to read until the next customer came in. He would be the 19 person in the world to say he was a hero. But he gave three people something they were badly in need of —a20 amount of self-respect and a little bit of hope.