(每题的备选答案中，有2个或2个以上符合题意，至少有1个错项。) 建设投资，由设备工

下列离子方程式不正确的是 （  ）

A．Na₂S溶液中滴加NaClO溶液：

S^2- + ClO^- + H₂O ="=" S↓ + Cl^- + 2OH^-

B．向NaHCO₃溶液中滴加NaAlO₂溶液：

HCO₃^- + AlO₂^- + H₂O ="=" Al（OH）₃↓ + CO₃^2-

C．NaHSO₄溶液中加入Ba（OH）₂溶液至溶液呈中性：

Ba²⁺ + OH^- + SO₄^2- + H⁺ ==BaSO₄ ↓+ H₂O

D．向30ml 0.5mol·L^-1NaOH溶液中通入224mL（标准状况）CO₂：3OH^- + 2CO₂ ="=" CO₃^2- + HCO₃^- + H₂O

（一）写出有关反应的离子方程式：

（1）硫酸氢钠溶液与碳酸氢钠溶液的反应______；                                              

（2）硫化亚铁投入稀硫酸中反应______；

（3）向Na₂CO₃溶液中加入少量稀盐酸______；

（4）向碳酸氢钙溶液中加入少量烧碱溶液______．

（二）某无色溶液，由Na⁺、Ag⁺、Ba²⁺、Al³⁺、Al

O

-2

、Mn

O

-4

、C

O

2-3

、S

O

2-4

中的若干种组成，取该溶液进行如下实验：

①取适量试液，加入过量盐酸，有气体生成，并得到溶液；

②在①所得溶液中再加入过量碳酸氢铵溶液，有气体生成；同时析出白色沉淀甲；

③在②所得溶液中加入过量Ba（OH）₂溶液，也有气体生成，并有白色沉淀乙析出．

根据上述实验回答下列问题：

（1）溶液中一定不存在的离子是______；

（2）一定存在的离子是______．

出现( )情况，设备供货方应承担违约责任。

A．未通知而提前交货

B．未提交保修单

C．未交付定金

D．未履行担保

阅读理解。

     "Christmas comes but once a year" is a familiar phrase, and indeed for many people the 25th of December

is the highlight of the calendar (日历).

     But for one British man once a year is not enough. Andy Park, who is better known by his nickname

Mr. Christmas, has celebrated Christmas every single day for the last 14 years.

     The 44-year-old electrician claims to have eaten a full roast dinner every day for the last decade and a half,

munching over 5 000 turkeys, 117 000 Brussels sprouts, and around 30 000 roast potatoes in the process.

     He also sends himself a Christmas card every day and looks forward to unwrapping a present he has

bought himself each evening, while watching the Queen's Speech.

     Mr. Park estimates his festive love costs him ￡150 (1570 yuan) a week. This year, however, he says he

is short of money for his celebrations due to the global financial crisis.

     His Christmas habit is affecting more than just his wallet. Mr. Park was previously warned by his doctor

that his Christmas addiction could kill him. His habit has caused his weight to 121kg.

     So how did Andy Park's strong desire for Christmas begin?

     "I'll never forget the day it started," said Mr. Park. "The sun was shining, but I was just feeling fed up and

bored, so I went home and put the decorations up. Suddenly I was happy. I thought, this is fun. So I did it

again the next day, and the day after that."

1. What's the best title for this text?

A. Mr. Christmas

B. Habit and weight

C. Christmas celebrations

D. A strong desire for Christmas

2. Which of the following underlined words in the text has the closest meaning to "eat"?

A. unwrap.

B. munch.

C. claim.

D. estimate.

3. What problem does Mr. Christmas now have?

A. His festive love costs him 150 pounds a week.

B. He doesn't have enough money for Christmas.

C. He often feels fed up and bored with his celebrations.

D. His doctor warned him against celebrating Christmas.

4. We can learn from Mr. Christmas's habit that _____.

A. every coin has two sides

B. all roads lead to Rome

C. there is no smoke without fire

D. an early bird catches worms

某一双链DNA分子含有800个碱基对，其中含A600个。该DNA分子连续复制了数次后，消耗环境中含G的脱氧核苷酸6200个，则该DNA分子已经复制了：（）

A.4次

B.5次

C.6次

D.7次