一条弦把圆的一条直径分成2cm和6cm两部分，若弦与直径所成的角为30°，则圆心

有一质点在连续12s内做匀加速直线运动，在第一个4s内位移为24m，在最后4s内的位移为56m，则：   （   ）                                             

A．质点的加速度为1m/s²

B．质点运动的初速度为1．5m/s

C．质点在12s内的平均速度为12m/s

D．质点10s末时的速度为14m/s

蔡元培是浙江（）人。

近年来，“大宗商品源源不断从其他新兴经济体流入中国，这些国家由于出口激增收入增加进而增加对中国制成品的消费——中国通过自身的高速增长，打开了新兴市场经济增长的阀门”。这一材料表明（）

A.中国制成品的进口超过出口

B.中国已成为发达经济体成员

C.新兴经济体的经济合作加深

D.新兴经济体的经济竞争加剧

Compared with IBM, Microsoft is a mere young company. Founded in 1975, it rose swiftly to dominate the world of personal computing with its Windows operating system and Office suite of word-processing and other productivity tools. But the company is now showing some worrying signs of middle-age fatigue. In particular, it is struggling to find a growth strategy that will enthuse disappointed shareholders.

Complaint are understandable. Since Steve Ballmer took over from Bill Gates as chief executive in 2000, Microsoft’s share price has decreased and the company has lost its reputation as a tech trend-setter. It has been left behind in hot areas such as search and social networking by younger companies, some of which love to thumb their noses at their older rival. Eric Schmidt, the executive chairman of Google, recently proclaimed that leadership in the tech world had passed from Microsoft and others to a "Gang of Four" fast-growing, consumer-oriented businesses: Google, Apple, Amazon and Facebook.

Few would object to that. The question is: what，if anything, can Microsoft do to change it In at least some respects, the company appears to be suffering from similar ailments to those that laid IBM low before Lou Gerstner was hired in 1993 to get it back on its feet. These include arrogance bred of dominance of a particular area-mainframe computers at IBM, personal computers at Microsoft—and internal fiefs that hamper swift change.

As IBM’s experience shows, recovery in the tech world is possible. And some observers see encouraging signs of progress at Microsoft. Sarah Rotman Epps of Forrester, a research firm, reckons that Windows 8, a forthcoming version of Microsoft’s operating system, could be a serious competitor to Google’s Android on tablet computers if the company can get it to market next year．Microsoft is also in far better shape financially than IBM was at its lowest point, so it can afford to splash out on acquisitions such as its recent $8.5 billion purchase of Skype, an internet-phone and video-calling service.

That bet and an alliance with Nokia in mobile phones show that Microsoft is trying to bulk up in promising areas. Yet sceptics worry that such initiatives are not the product of an comprehensive strategic vision, but are instead temporary moves designed to calm critics who fear Microsoft is drifting downwards. David Einhorn, a prominent hedge-fund manager whose fund holds shares in Microsoft, has publicly called for a change at the top of the firm, arguing that Mr Ballmer is "stuck in the past". So far, the company’s board, chaired by Mr Gates, has backed its chief executive. But if IBM’s history is a guide, Microsoft may yet end up jettisoning its leader.

According to the text, which of the following is true of Microsoft（）

A. It is considering hiring a new CEO

B. It is engaged in an internal reform

C. It can rival IBM in mainframe computers

D. It is committing the mistakes IBM once committed

安全教育和培训按等级、层次和工作性质分别进行，操作者的重点是（）。

A、安全管理水样

B、安全生产意识和安全管理水平

C、操作能力

D、遵章守纪、自我保护和提高防范事故的能力