使用高渗溶液可以在一定程度上防止食品腐败，但其不属于防腐措施的一种。

已知函数y=(k2+k)xk2-2k-1是二次函数，它的图象开口______，当x______时，y随x的增大而增大．

Read the following text and choose the most suitable heading from A-F for each paragraph. There is one extra heading which you do not need.

PARIS

小题1:Paris, the capital and the largest city of the country, is in north central France. The Paris metropolitan area contains nearly 20% of the nation’s population and is the economic, cultural, and political center of France. The French government has historically favored the city as the site for all decision making, thus powerfully attracting nearly all of the nation’s activities.

小题2:Paris has grown steadily since it was chosen as the national capital in the late 10^th century. With the introduction of the Industrial Revolution, a great number of people moved to the city from the country during the 19^th century. The migration was especially stimulated by the construction of railroads, which provided easy access to the capital. After World War II more and more immigrants arrived.

小题3:The city is the centralized control point of most national radio and television broadcasting. It is a place of publication of the most prestigious (有威望的) newspapers and magazines and an international book publishing center. With more than 100 museums, Paris has truly one of the greatest concentrations of art treasures in the world. The Louvre, opened as a museum in 1793, is one of the largest museums in the world.

小题4:In the late 1980s about 4.1 million pupils annually attended about 47,000 elementary schools. In addition, about 5.4 million students attended some 11,200 secondary schools. Approximately 1.2 million students were enrolled annually at universities and colleges in France in the late 1980s. French centers of learning have served as academic models throughout the world.

小题5:Paris is the leading industrial center of France, with about one quarter of the nation’s manufacturing concentrated in the metropolitan area. Industries of consumer goods have always been drawn to Paris by the enormous market of the big population; and modern, high-technology industries also have become numerous since World War II. Chief manufactures are machinery, automobiles, chemicals and electrical equipment.

（12分）学习卤代烃性质时，我们知道溴乙烷在不同溶剂中与氢氧化钠发生不同类型的反应，生成不同的反应产物。我们可以通过实验的方法去验证反应的产物：

（1）在溴乙烷与氢氧化钠的乙醇溶液的                     （反应类型）中可以观察到有气体生成。某同学用如下图所示装置对该气体进行验证，他所观察到的现象是                                               ；

（2）盛水试管的作用是                   ；

（3）除了用酸性高锰酸钾溶液外，还可以用                              试剂检验该气体，其反应原理是                                        （用化学方程式表示）。

（4）另一位同学取少量溴乙烷与氢氧化钠水溶液反应后的混合溶液，向其中滴加硝酸银溶液，加热，产生少量沉淀。该同学由此得出溴乙烷与氢氧化钠水溶液反应，生成了溴化钠。老师和同学都认为这样不合理。若请你用实验验证该反应中生成了溴化钠，你与该同学实验方案不同的实验方法是                                          。

顺元散功效与作用

向某HNO₃和Fe(NO₃)₃的混合稀溶液中逐渐加入铁粉，产生无色气体，该气体遇空气变红棕色，溶液中

Fe²⁺浓度和加入Fe粉的物质的量之间的关系如图所示，则原稀溶液中HNO₃和Fe(NO₃)₃的物质的量浓度之比为

A．4:1

B．3:1

C．2:1

D．1:1