将2.3g钠投入到97.8g水中，反应完毕后，得到100mL的溶液．求：

Liu Xiang is believed _________ over $ 20 million in advertisements last year alone.

下列各组粒子中属于同位素的是（   ）

TMB是一种新型指纹检测的色原试剂，由碳、氢、氮三种元素组成，M=240g/mol。某研究性学习小组的同学欲利用下列仪器测定TMB的分子式。主要过程为在足量氧气流中将4.80 g TMB样品氧化(氮元素转化为N₂)，再利用吸收剂分别吸收水蒸气和CO₂。请从图中选择适当的装置(装置符合气密性要求，加热装置等已略去，其他用品可自选)。

阅读下面的材料，根据要求写作。

从 2020年3月5日晚开始，一张照片在朋友圈刷屏：夕阳西下，阳光撒向大地，一名医生和一位躺在病床上的患者一同望向夕阳。照片来自武汉大学人民医院东院。3月5日傍晚，援鄂的上海中山医院医生刘凯，陪卧床老人做CT途中，询问老人：“要不要看一眼夕阳？”于是有了这令人动容的一幕。一个是年近九旬的重病患者，一个是从业未久的年轻医生，在这场严峻的考验面前，可能都曾有过惶恐、灰心、失落。

报道里说，这位患者刚入院时病情危重、心情低落，甚至拒接家人电话。而在这个下午的那一刻，两个生命在夕阳之下的背影给我们带来一种莫名的感动。

在这样一个举国同抗新冠疫情的特殊时期，你对以上内容有什么触动、启发和思索？请分享给你的好友，给他写一封信表达你的思想感悟。

要求：结合材料，自选角度，确定立意；切合身份，贴合背景；符合文体特征；不要套作，不得抄袭；不得泄露个人信息；不少于800字。

这个标记代表什么?(represent)

根据下列几种粒子的结构示意图，回答问题：

（1）其中属于阴离子的是　 　（填字母编号），化学式为　 　

（2）属于金属元素的是　 　（填编号），用​来表示该原子的组成　 　．

（3）具有相似化学性质的是　 　（填编号）．

这个小孩子不能被要求做如此困难的事情。(make)

下列组合属于同位素的是 (    )

在△ABC中，内角A、B、C的对边分别为a、b、c，若 ，且 ，则△ABC一定是（    ）

下列说法正确的是（   ）

Don't copy others' homework. You should do it your own.

They put an a in The Morning News, offering(提供)a high salary for the right person.

With the development of the Internet, you now can do some shopping .(足不出户)

When soldiers somewhere, they walk there with very regular steps as a group.

除了这里漂亮的风景,我还喜欢这个城市的历史和文化。

I like the city's history and culture its beautiful scenery.

I (not see) Ann for so long that I've forgotten what she looks like.

The doctor the nurse is talking is leaving for Africa next month.

将Na、Na₂O，Na₂O₂的混合物与足量的水反应，在标准状况下得到672mL混合气体，将混合气体通电后恰好完全反应，则Na、Na₂O，Na₂O₂的物质的量之比为（   ）

阅读理解

    I have two sons. They are as different as night and day. My youngest is sweet, loveable, easy-going, and finds joy in everything. My oldest we've nicknamed the “Evil Genius” is ambitious, self-confident, and suffers no fools. Whenever we mentioned Santa my husband and I were rewarded with major eye rolling and deep sighs from my oldest. At first we both tried to ignore it.

    We both knew that our eldest had figured out the big secret. But I'd be damned(指责) if he was going to ruin it for his six-year-old brother who had plenty of Santa-loving years ahead of him. I looked at my husband in the eye and said, “I'll handle this.” to which he responded “Okay just be careful because I'm not sure he knows - he might just be acting like it.” But I knew. And I had it in my mind that he was about to break his younger brothers spirit and break the news to him. I was afraid he was going to take the Christmas spirit away from my sweet innocent youngest and stamp all over it. I had to protect him. I needed to control this now before it got out of control. I rushed into the play room where my oldest was playing alone. I looked him dead in the eyes and said: “Well you know Santa isn't real, right?” And as I stared at my eight-year-old son for what seemed like a long time of silence, his eyes started to fill with tears. And a tear dropped down his cheek when he screamed out, “He's not?” “Um well it's not that he's not real (shut up you idiot- stop saying he's not real), but he doesn't really make and deliver all the toys. Dad and I get some of them for you. So he's real. He's just got a little help from us.”

    The Evil Genius wasn't buying it. He just sat there looking at me with an expression of doubt. You know when you make a terrible mistake but you can't stop yourself from making it worse? That was me because I just had to know. I had to know why he had seemed to be over Santa. So I asked him why he rolled his eyes and sighed every time his father and I mentioned Santa, to which he replied that kids at school had been saying Santa wasn't real but that he still thought he was.