什么是酶分子的化学修饰？有何作用？

建设项目中仓储设施建设方式受储存期和储存量等因素的影响，确定储存期时，应考虑的因素有( )。

A．物料的运输要求

B．物料的年消耗量

C．仓储的人员配备

D．物料特性要求

E．仓储的维修设施

下列有关中国现行房地产税各税种的纳税人，表述正确的是( )。

A．中国境内拥有房屋产权的单位和个人都是房产税的纳税人

B．产权属于全民所有的，以经营管理的单位和个人为房产税纳税人

C．土地使用税的纳税人是拥有土地使用权的单位和个人

D．在中华人民共和国境内转移土地、房屋权属，转让的单位和个人为契税的纳税人

E．有偿转让土地使用权、地上建筑物及其他附着物并取得收入的单位和个人为土地增值税的纳税人

阅读理解.

     I still remember my first day at school in London and I was half-excited and half-frightened.

On my way to school I wondered what sort of questions the other boys would ask me and

practiced all the answers: "I am nine years old. I was born here but I haven't lived here since

I was two. I was living in Farley. It's about thirty miles away. I came back to London two

months ago." I also wondered if it was the custom for boys to fight strangers like me, but

I was tall for my age. I hoped they would decide not to risk it.

     No one took any notice of me before school. I stood in the center of the playground,

expecting someone to say "hello", but no one spoke to me. When a teacher called my name

and told me where my classroom was, one or two boys looked at me but that was all.

     My teacher was called Mr. Jones. There were 42 boys in the class, so I didn't stand

out there, either, until the first lesson of the afternoon. Mr. Jones was very fond of Charles

Dickens and he had decided to read aloud to us from David Copperfield, but first he asked

several boys if they knew Dickens' birthplace, but no one guessed right. A boy called Brian,

the biggest in the class, said: "Timbuktu", and Mr. Jones went red in the face. Then he asked

me. I said: "Portsmouth", and everyone stared at me because Mr. Jones said I was right.

This didn't make me very popular, of course.

     "He thinks he's clever," I heard Brian say.

     After that, we went out to the playground to play football. I was in Brian's team, and he

obviously had Dickens in mind because he told me to go in goal. No one ever wanted to be

the goalkeeper.

     "He's big enough and useless enough." Brian said when someone asked him why he

had chosen me.

     I suppose Mr. Jones, who served as the judge, remembered Dickens, too, because

when the game was nearly over, Brian pushed one of the players on the other team, and

he gave them a penalty (惩罚). As the boy kicked the ball to my right, I threw myself down

instinctively (本能地) and saved it. All my team crowded round me. My bare knees were

injured and bleeding. Brian took out a handkerchief and offered it to me.

     "Do you want to join my gang (帮派)?" he said.

     At the end of the day, I was no longer a stranger.

1．The writer prepared to answer all of the following questions EXCEPT " ".

A. How old are you?

B. Where are you from?

C. Do you want to join my gang?

D. When did you come back to London?

2．We can learn from the passage that .

A. boys were usually unfriendly to new students

B. the writer was not greeted as he expected

C. Brian praised the writer for his cleverness

D. the writer was glad to be a goalkeeper

3．The underlined part "I didn't stand out" in paragraph 3 means that the writer was not .

A. noticeable

B. welcome

C. important

D. foolish

4．The writer was offered a handkerchief because .

A. he threw himself down and saved the goal

B. he pushed a player on the other team

C. he was beginning to be accepted

D. he was no longer a newcomer

加大前角能使车刀锋利、减少切屑变形、减轻切屑与前刀面的摩擦，从而（）切削力。

A、降低

B、增大

C、升高

[背景材料]

2005年9月7日，A市政府采购中心受M大学委托，就现代化办公设备及服务采购项目组织了采购项目的招标、开标、评标工作。M大学是财政拨款的事业单位。经评审，B公司中标，随后与M大学签订了政府采购合同。
2005年9月16日和20日，A市政府采购中心和A市财政局先后接到匿名举报，称B公司在该项目投标过程中存在串通投标的行为，要求调查核实。A市财政局组成了调查组开展调查，经调查，证明B公司与另一投标供应商C公司存在串通投标行为。但B公司否认串通投标。
调查小组取得的多个证据证明其串标行为，如参与投标的5家供应商中，只有B公司与C公司所投报的技术标书从“产品组成技术说明”、“产品的技术服务和销售服务内容及措施”到“投标货物明细表”中包括计算机、服务器和投影仪在内的投标明细表连续41页的内容、格式和排版完全相同；C公司报价均高于B公司；经委托公安机关技术鉴定，确认2份投标文件相同部分出自一个电子文本。
经原评标委员会审查，出具了对2份投标文件的认定情况，认为B公司与C公司在本次招标投标活动中存在串通投标行为。而且C公司项目负责人承认了串通投标的事实经过，并提供了证言和通话记录等证明材料。
A市财政局于2005年10月27日作出处理决定：撤销B公司与M大学的合同，处中标额10%的罚款，并列入不良记录名单，禁止B公司3年内、C公司1年内参加政府采购活动。2006年3月9日B公司不服A市财政局的行政处罚，向A市东安区人民法院提起行政诉讼。
B公司认为：A市财政局的行政处罚决定没有任何事实根据，所适用的法律违反了处罚法定的基本原则，进行的行政处罚在程序上也严重违法，要求法院撤销行政处罚告知书及其相应行政处罚决定。
2007年1月17日，法院作出判决：“维持A市财政局行政处罚决定”。
B公司不服判决，于2007年2月2日向A市中级人民法院提起上诉。法院开庭审理，于2007年4月5日，作出判决：“驳回上诉，维持原判”。

[问题]

A市财政局是否有权撤销B公司与M大学的合同，为什么