标准直齿柱齿轮的周节等于π与（）相乘

读下列文字及相关简图后，回答问题。

材料一：

下图是我国2001年至2007年能源生产与消费变化图。

材料二：

    近年来，世界各国都越来越重视各类能源的开发，我国东部沿海地区已建和在建的核电分布如下表所示，而在西部地区则重点开发风电等能源。

（1）从2001年到2007年，我国能源生产和消费的变化特点是__________________________________________________________________________________________。

（2）按应用程度来说，核能属于_______，此类能源还包括_______、_______、_______、_______等。

（3）新疆和内蒙古的风能资源都很丰富，对其合理的认识是_______。（填字母）

A．两地接近冬季风源地，风速较大，是这里风能资源丰富的主要原因

B．建设三北防护林将会使这些地区风速降低，不利于我国风能的开发

C．由于两地均以高原地形为主，有利于风电场的建设

D．新疆面积大于内蒙古，故该省区风能资源要明显大于内蒙古

（4）近几年来我国将内蒙古作为风能重点开发地区，其主要原因是什么？从上海目前状况来看，风能开发已经起步，上海发展风能的优势是什么？

___________________________________________________________________________________________

（5）从所给材料来看，我国将核能开发重点放在了东部沿海地区，其主要原因是什么？（至少三点）

___________________________________________________________________________________________

（6）受日本地震核泄漏事件影响，你认为我国核能开发需借鉴的经验是什么？（至少两点）

___________________________________________________________________________________________

美国国会每两年为一届，它由参议院和众议院组成，参议院代表州，众议院代表选民，材料中关于参议院的说法正确的是                                     

A．参议院中，每个州不论大小都有参议员两人，以体现各州在联邦中的平等地位

B．参议员任期六年，每两年改选三分之一

C．参议员任期两年，任期届满全部改选

D．席位按各州人口与全国人口的比例分配到各州

阅读理解

     My family and I lived across the street from Southway park since I was four years old.Then just last

year the city put a chain link fence around the park and started bulldozing(用推土机推平)the trees and

grass to make way for a new apartment complex.When I saw the fence and bulldozers, I asked myself, "Why don't they just leave it alone?"

     Looking back, I think what sentenced the park to oblivion(被遗忘)was the drought(旱灾)we had

about four years ago.Up until then, Southway Park was a nice green park with plenty of trees and a

public swimming pool.My friends and I rollerskated on the sidewalks, climbed the trees, and swam in the

pool all the years I was growing up.The park was almost like my own yard.Then the summer I was fifteen

the drought came and things changed.

     There had been almost no rain at all that year.The city stopped watering the park grass.Within a few

weeks I found myself living across the street from a huge brown desert.Leaves fell off the park trees, and

pretty soon the trees started dying, too.Next, the park swimming pool was closed.The city cut down on

the work force that kept the park, and pretty soon it just got too ugly and dirty to enjoy anymore.

     As the drought lasted into the fall, the park got worse every month.The rubbish piled up or blew

across the brown grass.Soon the only people in the park were beggars and other people down on their

luck.People said drugs were being sold or traded there now.The park had gotten scary, and my mother

told us kids not to go there anymore.

     The drought finally ended and things seemed to get back to normal, that is, everything but the park.It

had gotten into such bad shape that the city just let it stay that way.Then about six months ago I heard

that the city was going to"redevelop"certain wornout areas of the city.It turned out that the city had

planned to get rid of the park, sell the land and let someone build rows of apartment buildings on it.

     The chainlink fencing and the bulldozers did their work.Now we live across the street from six rows

of apartment buildings.Each of them is three units high and stretches a block in each direction.The

neighborhood has changed without the park.The streets I used to play in are jammed with cars now.

Things will never be the same again.Sometimes_I_wonder, though, what_changes_another_drought_

would_make_in_the_way_things_are_today.

1. How did the writer feel when he saw the fence and bulldozers?

A. Scared.      

B. Confused.  

C. Upset.  

D. Curious.

2. Why was the writer told not to go to the park by his mother?

A. It was being rebuilt.

B. It was dangerous.

C. It became crowded.

D. It had turned into a desert.

3. According to the writer, what eventually brought about the disappearance of the park?

A. The drought.

B. The crime.

C. The beggars and the rubbish.

D. The decisions of the city.

4. The last sentence of the passage implies that if another drought came, ________.

A. the situation would be much worse

B. people would have to desert their homes

C. the city would be fully prepared in advance

D. the city would have to redevelop the neighborhood

有6瓶白色固体试剂，分别是氯化钡、氢氧化钠、硫酸钠、硫酸铵、无水硫酸铜、碳酸钠，现只提供蒸馏水，通过下面的实验步骤即可签别它们．请填写下列空白：

（1）各取适量固体试剂分别加入6支试和中，加入适量蒸馏水，振荡试管，观察到的现象是______被检出的物质的化学式（分子式）是______

（2）分别取未检出的溶液，往其中加入上述已检出的溶液，观察到的现象和相应的离子方程式分别为：

1支试管中有白色沉淀生成：______．

2支试管中有蓝色沉生成：______、______．

被检出的物质的化学式（分子式）是______

（3）鉴别余下未检出物质的方法和观察到的现象

（i）分别取（2）中能产生蓝色沉淀的两种溶液，向其中加入BaCl₂溶液，有白色沉淀生成的是______，无沉淀生成的是______．

（ii）分别取少量未检出的溶液，往其中加入NaOH溶液，无明显现象的是______，有刺激性气味气体产生的是______．

数据并发操作通常会带来三类问题，它们是丢失更新、______和对未提交更新的依赖。