在隔年枝条上开花的灌木，可以在休眠期重剪

无粘性预应力混凝土

信息时代产生的大量电子垃圾对环境造成了极大的威胁。某“变废为宝”学生探究小组将一批废弃的线路板简单处理后，得到含70%Cu、25%Al、4%Fe及少量Au、Pt等金属的混合物，并设计出如下制备硫酸铜晶体的路线：

回答下列问题：

⑴第①步Cu与酸反应的离子方程式为                                      ；得到滤渣1的主要成分为               。

⑵第②步加入H₂O₂的作用是                                     ，使用H₂O₂的优点是                                ；调节pH的目的是使            生成沉淀。

⑶用第③步所得CuSO₄·5H₂O制备无水CuSO₄的方法是                      。

⑷由滤渣2制取Al₂(SO₄)₃·18H₂O，探究小组设计了三种方案：

上述三种方案中，     方案不可行，原因是                               ；

从原子利用率角度考虑，       方案更合理。

⑸探究小组用滴定法测定CuSO₄·5H₂O(M_r=250)含量。取a g 试样配成100 mL溶液，每次取20.00 mL，消除干扰离子后，用c mol/L EDTA(H₂Y^2－)标准溶液滴定至终点，平均消耗EDTA溶液b mL。滴定反应如下：Cu²⁺+ H₂Y^2－＝CuY^2－+ 2H⁺

写出计算CuSO₄·5H₂O质量分数的表达式ω＝                           ；

下列操作会导致CuSO₄·5H₂O含量测定结果偏高的是         。

a．未干燥锥形瓶

b．滴定终点时滴定管尖嘴中产生气泡

c．未除静可与EDTA反应的干扰离子

解除有机磷中毒毒蕈碱样毒性作用，首选( )

A．阿托品
B．碘解磷定
C．美解眠
D．尼可刹米
E．甘露醇

阅读理解

     You may know your mother, but how well do you really know Mother's Day? Cards, flowers, sales,

TV specials, and a day off for someone who really deserves it ---- those are what probably come to

mind for many people when they think of Mother's Day. But there's more to the story.

     The earliest Mother's Day celebrations were held during spring in ancient Greece. The celebrations

honored Rhea, the Mother of the gods. During the 1600's, England celebrated a day called Mothering

Sunday. On this day even servants were given the day off to spend with their families. A mothering cake

was even served with the family meal.

      In the US, Mother's Day began in 1872 when Julia Ward Howe, who wrote the words to the famous

song The Battle Hymn of the Republic, suggested it as a day devoted to peace. But it didn't really become popular until 1907 when Anna Jarvis stared a campaign to honor mothers. She believed that mothers

could help people get over the pain they experienced during the Civil

     War. The US isn't alone in devoting a day to mothers. Many other countries including Denmark,

Finland, Italy, Turkey, Australia, Japan, and Belgium also honor their mothers in May. Other countries

honor their mothers at different times of the year.

     Learning more about Mother's Day and celebrating Mother's Day are important, but probably not as

important as understanding what your own mother, or grandmother, or aunt has really done for you.

And that will certainly be appreciated more than one day in a year.

1. What is the passage mainly about?

A. The reason why people celebrate Mother's Day.

B. The ways people honor mothers.

C. The history of Mother's Day.    

D. The great contribution of mothers.

2. Where was the earliest Mother's Day celebrated?

A. In ancient Greece.

B. In the US.

C. In England.

D. In Italy.

3. We can learn from the passage that _____.

A. Rhea is the mother of a king in ancient Greece

B. not all the countries celebrate Mother's Day in May

C. only mothers were given a day off on Mothering Sunday

D. it was in 1872 that Mother's Day really came into being

4. The last paragraph tells us that _____.

A. all the people should celebrate Mother's Day

B. only mothers are honored on Mother's Day

C. understanding mothers' work is more important than just celebrating Mother's Day

D. people should celebrate Mother's Day every day

A公司2008年发生下列业务：(1)4月，处置交易性金融资产(股票)，账面成本400万元，实际售价为550万元；(2)5月，处置交易性金融资产(债券)，账面成本300万元，实际售价为300万元；(3)6月，本年一项债券投资已到期，收回本金和利息；面值1300万元，利率为 11%，3年期，到期一次还本付息；(4)本年收到现金股利30万元。企业现金流量表中“收回投资所收到的现金”项目的金额为( )万元。

A．2180
B．2896
C．2150
D．2500