等差数列{an}中,a2+a7+a15=12,则a8=( ) A.2 B.3 C

题型:选择题

问题:

等差数列{an}中,a2+a7+a15=12,则a8=(  )

A.2

B.3

C.4

D.6

考点:等差数列的定义及性质
题型:选择题

Passage One

The world is going through the biggest wave of mergers and acquisitions ever witnessed. The process sweeps from hyperactive America to Europe and reaches the emerging countries with unsurpassed might. Many in these countries are looking at this process and worrying: "Won’t the wave of business concentration turn into an uncontrollable anti-competitive force"

There’s no question that the big are getting bigger and more powerful. Multinational corporations accounted for less than 20% of international trade in 1982. Today the figure is more than 25% and growing rapidly. International affiliates account for a fast-growing segment of production in economies that open up and welcome foreign investment. In Argentina, for instance, after the reforms of the early 1990s, multinationals went from 43% to almost 70% of the industrial production of the 200 largest firms. This phenomenon has created serious concerns over the role of smaller economic firms, of national businessmen and over the ultimate stability, of the world economy.

I believe that the most important forces behind the massive M&A wave are the same that underlie the globalization process: falling transportation, and communication costs, lower trade and investment barriers and enlarged markets that require enlarged operations capable, of meeting customers’ demands. All these are beneficial, not detrimental to consumers. As productivity grows, the world’s wealth increases.

Examples of benefits or costs of the current concentration wave are scanty. Yet it is hard to imagine that the merge of a few oil firms today could recreate the same threats to competition that were feared nearly a century ago in the U.S., when the Standard Oil trust was broken up. The mergers of telecom companies, such as World Corn, hardly seem to bring higher prices for consumers or a reduction in the pace of technical progress. On the contrary, the price of communications is coming down fast. In cars, too, concentration is increasing—witness Daimler and Chrysler, Renault and Nissan—but it does not appear that consumers am being hurt.

Yet the fact remains that the merger movement must be watched. A few weeks ago, Alan Greenspan warned against the megamergers in the banking industry. Who is going to supervise, regulate and operate, as lender of last resort with the gigantic banks that are being created Won’t multinationals shift production from one place to another when a nation gets too strict about infringements to fair corn petition And should one country take upon itself the role of "defending competition" on issues that affect many other nations, as in the U. S..

What is the typical trend, of businesses today ?()

A.To take in more foreign funds.

B.To invest more abroad.

C.To combine and become bigger.

D.To trade with more countries.

题型:选择题

帷幕灌浆采用自下而上分段灌浆法时,灌浆孔封孔应采用( )。

A.分段灌浆封孔法

B.置换和压力灌浆封孔法

C.压力灌浆封孔法

D.机械压浆封孔法

E.分段压力灌浆封孔法

题型:选择题

男性,40岁,痔疮出血1年,乏力、面色苍白3个月,查体:贫血貌,巩膜无黄染。血象:白细胞4.6×109/L.红细胞3.9×1012/L.Hb65g/L。血小板330×109/L。

下列哪项检查准确性和敏感性最高()

A.血清铁总铁结合力

B.血清铁

C.血清铁蛋白

D.红细胞内游离原卟啉测定

E.血清铁饱和度

题型:选择题

某同学用图所示装置粗略测定空气中氧气的体积分数,烧杯上方玻璃管中部有一可左右移动的活塞,活塞左端密封有空气,活塞右端玻璃管口与空气相通,开始时活塞在刻度5处,向烧杯内加水与生石灰反应放热使白磷燃烧,实验结束后活塞停留在(  )

A.6处

B.5处

C.4处

D.1处

题型:选择题

男,3岁,7月1日发病,发热5天,头痛,神志不清,烦躁不安2天,大便2次/日,颈强直,布氏征(+),深反射稍亢进,浅反射迟钝,周围血象:白细胞14×109/L,N0.82,E0.03,L0.15,脑脊液:白细胞220×106/L,N0.38,L0.62,糖3.1mmol/L,氯化物119mmol/L,蛋白1.2g/L。涂片和培养细菌均阴性,显凝试验1:100,考虑诊断为()

A.钩端螺旋体病(脑膜脑炎型)

B.流行性脑脊髓膜炎

C.流行性乙型脑炎

D.脑型疟疾

E.中毒性菌痢

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