肺结核常见的X线征象是（） A.毛刺征 B.反S征 C.梅花瓣征 D.卷发征 E.分

病毒抗原检测技术包括（）

A.细胞培养

B.免疫荧光

C.酶免疫

D.发光免疫分析

E.免疫层析

对硝基甲苯是医药、染料等工业的一种重要有机中间体，它常以浓硝酸为硝化剂，浓硫酸为催化剂，通过甲苯的硝化反应制备。

一种新的制备对硝基甲苯的实验方法是：以发烟硝酸为硝化剂，固体NaHSO₄为催化剂（可循环使用），在溶剂中，加入乙酸酐（有脱水作用），45℃反应1h 。反应结束后，过滤，滤液分别用5% NaHCO₃，溶液、水洗至中性，再经分离提纯得到对硝基甲苯。

(1)上述实验中过滤的目的是__________。

(2) 滤液在分液漏斗中洗涤静置后，有机层处于__________层（填“上”或“下”）；放液时，若发现液体流不下来，其可能原因除分液漏斗活塞堵塞外，还有__________。

(3) 下列给出了催化剂种类及用量对甲苯硝化反应影响的实验结果。

①NaHSO₄催化制备对硝基甲苯时，催化剂与甲苯的最佳物质的量之比为_____________。

②由甲苯硝化得到的各种产物的含量可知，甲苯硝化反应的特点是______________。

③与浓硫酸催化甲苯硝化相比，NaHSO₄催化甲苯硝化的优点有____________、___________。

胃肠道透视用BaSO4的制备方法是（）

A.机械分散法

B.超声分散法

C.物理凝聚法

D.化学凝聚法

E.溶解法

相对方向，右转车辆应当让左转车辆先行涉及（）的范畴。

A.空间路权

B.时间路权

C.完全路权

D.部分路权

Washington, DC has traditionally been an unbalanced city when it comes to the life of the mind. It has great national monuments, from the Smithsonian museums to the Library of Congress. But day-to-day cultural life can be thin. It attracts some of the country’s best brains. But far too much of the city’s intellectual life is devoted to the minutiae of the political process. Dinner table conversation can all too easily turn to budget reconciliation or social security.

This is changing. On October 1st the Shakespeare Theatre Company opened a 775-seat new theatre in the heart of downtown. Sidney Harman hall not only provides a new stage for a theatre company that has hitherto had to make do with the 450-seat Lansburgh Theatre around the corner. It will also provide a platform for many smaller arts companies.

The fact that so many of these outfits are queuing up to perform is testimony to Washington’s cultural vitality. The recently-expanded Kennedy Centre is by some measures the busiest performing arts complex. But it still has a growing number of arts groups which are desperate for mid-sized space down- town. Michael Kahn, the theatre company’s artistic director, jokes that, despite Washington’s aversion (厌恶) to keeping secrets, it has made a pretty good job of keeping quiet about its artistic life. The Harman Centre should act as a whistle blower.

Washington still bows the knee to New York and Chicago when it comes to culture. But it has a good claim to be America’s intellectual capital. It has the greatest collection of think-tanks on the planet, and it regularly sucks in a giant share of the country’s best brains. Washington is second only to San Francisco for the proportion of residents twenty-five years and older with a bachelor’s degree or higher.

Washington’s intellectual life has been supercharged during the Bush years, despite the Decider’s aversion to ideas. September 11th, 2001, put questions of global strategy at the center of the national debate. Most of America’s intellectual centers are firmly in the grip of the left-liberal establishment. For all their talk of "diversity" American universities are allergic to a diversity of ideas. Washington is one of the few cities where conservatives regularly do battle with liberals. It is also the center of a fierce debate about the future direction of conservatism.

The danger for Washington is that this intellectual and cultural renaissance will leave the majority of the citizens untouched. The capital remains a city deeply divided between over-educated white itinerants and under- educated black locals. Still, the new Shakespeare theatre is part of job-generating downtown revival. Twenty years ago downtown was a desert of dilapidated(破旧的) buildings and bag people. Today it is bustling with life. If Washington is struggling to fix the world, at least it is making a reasonable job of fixing itself.

According to the text, which of the following statements is correct（）

A. sidney Harman hall provides a new stage for Shakespeare Theatre Company

B. michael Kahn is the artistic director of the expanded Kennedy Centre

C. lansburgh Theatre is in the heart of downtown area in Washington

D. many smaller arts groups are desperate for mid-sized space downtown