脑挫裂伤后2～3日，病灶周围常伴有下列何种类型的脑水肿（）。 A.血管源性脑水肿 B

如图所示电路中，定值电阻R大于电源内阻r，当滑动变阻器滑动端向右滑动后，理想电流表A₁、A₂、A₃的示数变化量的绝对值分别为△I₁、△I₂、△I₃，理想电压表示数变化量的绝对值为△U，下列说法中正确的是（　　）

A．电流表A₂的示数一定变小

B．电压表V的示数一定增大

C．△I₃一定大于△I₂

D．△U与△I₁比值一定小于电源内阻r

按要求填空：

（1）写出下列反应的化学方程式：

①镁和水反应 ___________________________________________

②氧化铝和氢氧化钠溶液反应_______________________________________

③硅酸钠溶液露置在空气中变质 __________________________________________

（2）写出表示含有8个质子，10个中子的原子的化学符号：             ；

在H、H、H中共有       种原子，它们能形成        种氢气分子。

（3）某简单微粒的结构示意图为且X、Y 均为不大于20的正整数，据此回答下列问题：

①若呈电中性时该微粒不易与其它物质发生反应，这种微粒的符号是        ；

②若该微粒为负一价阴离子，则x＝     ，该元素的最高价氧化物的化学式为               。

⑷某元素的最高正价与最低负价的代数和为4，且最高价氧化物中含氧质量分数为60%。则该元素的气态氢化物化学式为                 。

（1）氯气具有以下性质：①在常温下是黄绿色气体；②在标准状况下，密度比空气大：③加热时，能和铁作用生成氯化铁；④有特殊刺激性气味；⑤溶于水生成具有漂白性能的次氯酸。在①-⑤中，属氯气物理性质的是（填序号）__________，属氯气化学性质的是__________。

（2）妈妈买回一袋新鲜的“蛋黄派”，袋内被气体充得鼓鼓的，这引起了我极大的兴趣。我大胆地猜测这种气体的作用是__________，这种气体可能是（填名称）__________。

阅读理解。

     The tower of Big Ben, London's most famous building, has always leaned (倾斜) slightly, but

construction work on a new line for the London Underground seemed likely to give the tower a

real lean. Engineers have had to prop up (支撑) its base to prevent it from damaging the rest of the

Houses of Parliament.

     To control the tower's movement,engineers pumped grout (水泥浆) into the soil under the tower.

The tower not leans an extra few centimeters, but the lean can only be seen by the most sharp-eyed

observer.

     Between 1995 and 1997, to lengthen the Jubilee line of the Underground, builders dug a

40-metre-deep hole just 31 metres north of the clock tower. And the new tube (underground ) tunnels

were even nearer to the tower. John Burland, who recently helped stop the increasing lean in the

Leaning Tower of Pisa and was an adviser to the Jubilee line project, believed the work would affect

the tower. In his opinion,no further lean should go beyond a safety limit of 27.5 millimetres over the

existing lean of 220 millimetres.

     To keep the lean within this limit,Burland told the British Association about the new method of

pumping grout immediately unde the base of the tower.More than 300 tons of grout were pumped

in during construction.The tower's additional lean went between 10 and 25 millimetres,but never

passed 27.5 millimetres.

      After the construction work was completed in last 1997, a review of movements in nearby walls

showed that the building was in better shape than had been thought before and the safety limit was

raised to 35 millimetres before any action needs to be taken.

     Since 1997,the tower had continued to lean, Burland told Modern Constuction.The latest

measurements,taken this year,suggest that the tower's lean had just reached 35 millimetres.But

following regular re-examinations of the tower,experts are sure that the tower has stabilised(稳定).

A spokesman for London Underground says: "We understand the tower has stabilised and retuned to

its normal movement cycle."

                                                                                   From Modern Construction, 16 September 2000

1. Which of the following drawings correctly shows how the propping up construction was carried out?

2. What does the word " review"(in Paragraph 5) mean?

A. Observation

B. Description

C. Discussion

D. Re-examination

3. Why was the propping up construction necessary?

A. To stop the tower of Big Ben from leaning

B. To stop sharp-eyed people from seeing the lean

C. To stop the Tower Pisa from leaning too much

D. To stop the clock tower from leaning beyond its safety limit

4. What was the existing lean of the tower at the time when the article was written?

A. 220 millimetres

B. 255 millimetres

C. 35 millimetres

D. 27.5 millimetres

5. We can infer from the article that _____.

A. the tower of Big Ben will damage the Houses of Parliament

B. the Jubilee line should be stopped in Burland's opinion

C. the writer is blaming Burland for making a mistake

D. the propping up work has proved to be successful

公平分配包括（）和（）两个层次。