某种氮的氧化物NxOy的式量与CO2式量相同，则NxOy的化学式为[ ] A．N

牙周病的致病菌不正确的是（）

A.牙周炎时龈下菌斑的量不变

B.健康牙周菌斑薄、细菌量少

C.牙龈炎时，菌斑中的细菌以革兰氏阳性杆菌为主

D.牙周炎时龈下菌斑中的革兰氏阴性菌增多

E.牙周炎时龈下菌斑中厌氧菌增多

有两只电压表A和B，量程已知，内阻未知，另有一节干电池，它的内阻不能忽略，也未知，只用这两只电压表、开关和一些连接用导线，通过测量计算出这个电池的电动势（已知电动势不超过电压表的量程，干电池不允许拆开）。

(1)画出你测量时所用的电路图；

(2)以测得的量作为已知量，导出计算电动势的式子。

砖的密度是2.0×10³kg/m³，一块砖的体积是1.4×10³cm³．则一辆能装载6t的汽车最多能运多少块这样的砖？

第二部分 阅读理解（共两节，满分50分）

第一节 阅读下列短文，从每题所给的四个选项（A、Ｂ、Ｃ和Ｄ）中，选出最佳选项，并在答题卡上将该项涂黑。（共20小题；每小题2分，满分40分）

Most American colleges and universities take a spring break. Students might go home to their families -- or spend a week partying on a warm beach with no parents around. That is the popular image, at least.

In the United States, the lawful age to drink alcohol is twenty-one -- one of the highest in the world. Americans debate whether it should be lowered, or whether young drinkers would only drink more. In parts of Europe, the lawful drinking age for beer, and sometimes hard liquor, is sixteen. Yet France may raise the age limit for beer and wine sales to eighteen, the same as for hard liquor there.

Rules on alcohol differ from college to college in the United States. Many schools require all first-year students to take an alcohol prevention and education program, often given online. Some have a “zero tolerance” policy where alcohol is banned from all buildings. Parents are informed of violations and students may be suspended(停学).

At the University of Virginia in Charlottesville, permission is needed to serve alcohol at any event on campus. But alcohol is banned in first-year dorms---where most students are under twenty-one anyway.

Susan Davis, a university lawyer, says campus police and local police report underage drinking violations(违反)to the committee that decides punishments on a case by case basis. For example, the committee might suspend or expel(开除)a student. It might require an alcohol education program. Or it might just give a warning.

Jon Zug is a lawyer in Albemarle County, where the university is located. He says international students would face the same punishment as American citizens for underage drinking in Virginia. That includes a punishment of five hundred dollars or fifty hours of community service. But first law-breakers might be given a chance to complete an alcohol education program instead.

Schools have to report unlawful violations by international students to the Department of Homeland Security. International adviser Richard Tanson at the University of Virginia says even minor violations stay on a student’s permanent immigration record. He says international students should know that this can affect them in the future if they try to re-enter the United States.

1. What does the underlined phrase “by case basis” mean?

A. Depending on the seriousness of the case itself.

B. According to the report of the campus and local police.

C. Depending on the judgment of the committee.

D. According to the former cases in store.

2. To international students, which of the following may be intolerable once they have drinking violations?

A. A punishment of $500 or 50 hours of community service.

B. Being given a warning of being suspended or expelled.

C. Having the violations kept on their permanent immigration record.

D. Receiving an alcohol education program.

3. The passage probably appears in_________.

A. an advertisement                                              B. a local newspaper  

C. a university guide book                                        D. a popular magazine

4. The passage mainly talks about_________.

A. alcohol problems on the U.S. campus    

B. alcohol policy on U.S. campus

C. U.S. universities---zero tolerance to alcohol

D. the punishment to the university alcohol drinkers

现代信息网络技术、微电子技术和虚拟技术，把人们的视野扩展到一个全新的领域。人们不公可以借助计算机技术建立作战实验室，把对历史经验的归纳和对未来的预测融为一体，将计算机自动推理与专家经验指导结合起来，而且能通过合成动态的人工模拟战场，造就逼真的作战环境，为战略理论研究开启新的渠道和广阔空间。许多国家以此为依据，提出新的作战原则和理论，并在此基础上形成了本国的国家安全战略，从而实现了国家安全谋划从经验决策到科学决策的转变。 这段文字意在强调（）

A.现代科技有助于科学制定国家安全战略

B.现代信息网络技术的发展革新了战争方式

C.国家安全谋划正从经验决策向科学决策转变

D.作战原则和理论依赖于科学技术的创新和发展