类推是化学学习中常用的思维方法。现有以下类推结果，其中正确的是 [ ] A．酸碱

原子序数依次增大的A、B、C、D、E、F、G七种短周期主族元素

①B元素的原子最外层电子数是次外层电子数的两倍，

②C的最高价氧化物的水化物和氢化物反应生成盐

③D和E可以形成1：1和1：2的两种常见化合物。

④A与C元素原子的电子层数相差1，且与E是同主族元素

⑤原子半径由大到小顺序是E>F>G＞B>C>D＞A

⑥F是同周期中离子半径最小的元素，G是同周期中原子半径最小的元素

回答：

（1）由B、D、E三元素组成的无机盐水溶液呈碱性，其原因是（用离子方程式表示）___________________________________　　　

（2）A的单质和D的单质可以设计为新型燃料电池，电解质为KOH溶液，则A的单质在该燃料电池中发生的电极反应式为__________________________。

（3）当反应3A₂（g）＋C₂（g）2CA₃（g）达到平衡时，不断改变反应条件(不改变A₂、C₂和CA₃的量)，下图表示反应速率与反应过程的关系，其中表示平衡混合物中CA₃的含量最高的一段时间是__________________。

（4）D和E能形成1：1和1：2的两种常见化合物X和Y ：写出Y与水反应的离子方程式：_________________________________。若将X、Y分别溶于等量足量的水中，形成浓度相同的溶液，需X、Y的物质的量的关系为： n（X）____________n(Y)(填“＜”“＞”或“＝”)

（5）C、D、E、F、G的简单离子的半径由大到小的顺序是（用元素的离子符号表示）________________

（6）F的最高价氧化物对应水化物的电离方程式为__________________________

（7）用离子方程式说明C与A形成的化合物结合H⁺能力强于D与A形成的化合物：___________________

作为使用工具的（），既是人工制品的鼻祖，也是造型艺术的端倪。

A.壁画

B.石器

C.物件装饰

D.雕塑

阅读理解

     The rumors had been spreading for months but it still came as a shock when the hospital would be

closing. It had served this poor neighborhood for nearly 100 years but it would close because of the health care crisis.

     The day after the announcement co-workers found out that pretzels(椒盐饼干) had been eliminated.

Soft pretzels are the lifeblood of this city. So losing access to soft pretzels is no small matter.

     A week later, I decided to cheer up my co-workers by picking up some soft pretzels at a local store.

I arrived just as it opened so I was the only customer. But I only had $6 in my wallet. I was working inside a large office at the hospital and knew I'd need more than the half dozen pretzels my six dollars would buy. A man's voice interrupted my thoughts. "Can I help you?"

     I said, "I only have $6. I'm not sure how many pretzels I need. You see, I work at a hospital and it's

closing and they stopped selling pretzels." The man's smile disappeared. "What hospital?" "Oh,

Northeastern Hospital."

     The guy looked deeply shocked. "I used to sell medical supplies and that was one of my hospitals."

Then he turned around and grabbed a box of 25 pretzels and slid them across the counter.

     I was surprised by his generosity and started to reach for my wallet, "Oh I can pay. Please let me …

The guy smiled, "Just tell them Joe Sullivan said to do something nice for someone else."

     And so that day everyone in medical records was treated to a soft pretzel. Word spread fast as people came asking, "Is it really true?" It was as if I'd carried in a box of gold. It mattered to them that a stranger

cared.

1.The underlined word "eliminated" in Paragraph 2 means _____.

A. highly priced

B. added

C. overcooked

D. removed

2.Why did the author decide to buy pretzels for his co-workers?

A. To show his generosity.

B. To make them feel less sad.

C. To show his thanks to them.

D. To encourage them to work hard.

3.To buy 25 pretzels, the author should pay ____.

A. $25

B. $12.5

C. $12

D. $50

4.According to the passage, Joe Sullivan used to be a ____.

A. cook

B. doctor

C. shopkeeper

D. salesman

5. What can be the best title of the passage?

A. A nice treat

B. The rumor that came true

C. Tell them Joe cared

D. Northeastern Hospital is closing down

中央型腰椎管狭窄下列正确的是（）

A.严重的症状和客观的体征不符

B.腰椎前屈一般不受影响

C.直腿抬高试验阳性

D.括约肌功能障碍多见

E.常反射减弱，踝反射消失

设A是三阶实对称矩阵，存在正交阵Q=[ξ₁，ξ₂，ξ₃]，使得Q^-1AQ=Q^TAQ=

，则矩阵B=A-ξ₁

的特征值是______．