劳动环境中有害因素的危害程度，主要取决于劳动者在劳动过程中接触有害因素的（）和有害因

城市人口增长过快导致的结果是[ ]

A．受教育机会增多

B．住房、交通拥挤

C．医疗卫生条件的改善

D．就业机会增加

为了验证动能定理，某学习小组在实验室组装了如图的装置外，还备有下列器材：打点计时器所用的学生电源、导线、复写纸、天平、细沙。他们称量滑块的质量为M、沙和小桶的总质量为m。当滑块连接上纸带，用细线通过滑轮挂上空的小桶时，滑块处于静止状态。要完成该实验，则：

⑴还缺少的实验器材是       。

⑵实验时为保证滑块受到的合力与沙、小桶的总重力大小基本相等，沙和小桶的总质量应满足的实验条件是      ，实验时为保证细线拉力等于滑块所受的合外力，首先要做的步骤是       。

⑶在⑵问的基础上，让小桶带动滑块加速运动，用打点计时器记录其运动情况，在打点计时器打出的纸带上取两点，测出该两点的间距为L、打下该两点时滑块的速度大小为v₁、v₂（v₁< v₂），已知当地的重力加速度为g。写出实验要验证的动能定理表达式        （用题中所给的字母表示）。

WASHINGTON——Chinese Vice-President Xi Jinping arrived at Andrews Air Force Base in Washington，February 13，2012．Vice-President Xi Jinping said he would explore important problems in an active and practical manner with his America hosts on Monday during his five-day official trip here after arriving at Andrews Air Force Base in the afternoon．

In a written statement given upon his arrival，Xi said as the international situation experiences complex and complete changes，China and the United States have more extensive common interests and shoulder more important common responsibilities on the present world stage.

The purpose of the current visit is to “carry out the important consensus reached by President Hu with President Obama during his visit to the United States in January last year and to advance the building of the China—US cooperative partnership based on mutual respect and mutual benefit”，said Xi.

According to Xi，bilateral(双边的)relations have moved forward in spite of some twists and turns during the past several decades．

“This has brought enormous benefits to our two countries and two peoples，and has had a positive, far-reaching impact on peace，stability and the prosperity of the Asia-Pacific region and the world at large”．

Xi said that“whether we can seize opportunities，tackle challenges and build a cooperative partnership at the new historical starting point matters to the future of our two countries and the world as a whole．”

Xi said he looks forward to engaging in extensive dialogue and exchanges with Americans from various sectors to enhance cooperation and strengthen friendship．

Xi is scheduled to meet US senior government officials，including Henry Kissinger，Brent Scowcroft，Zbigniew Brzezinski，Madeleine Albright and Henry Paulson this evening to listen to their advice on China-US ties．

Meetings between Xi and US Vice-President Biden and President Obama are scheduled on Tuesday.

小题1:The passage mainly tells us       .

A．Xi's five-day official trip

B．China-US cooperative partnership

C．Xi is set to discuss important bilateral problems

D．China and the US have more common interests小题2:It can be inferred from the second paragraph that     ．

A．the current world stage remains peaceful

B．China and US should build the cooperative partnership

C．Xi himself wrote a statement about his arrival

D．China and the US have the equal rights小题3:The underlined word“consensus”in Paragraph 3 means     ．

A．agreement

B．opinion

C．partnership

D．benefit小题4:According to tile passage，bilateral relations between China and US have experienced       ．

A．enormous dialogues

B．extensive exchanges

C．rnany challenges

D．various hardships小题5:What is Xi's attitude towards the visit?

A．Respectful．

B．Optimistic．

C．Approving．

D．Expectant．

GN型碱性蓄电池液面高度应在防护板（）以上。

A、5～10mm

B、10～15mm

C、15～20mm

D、20~25mm

有关紫癜正确的是（）

A.皮肤出现红色或暗红色斑，一般高于皮肤表面

B.皮肤出现红色或暗红色斑，发生的充血现象

C.皮肤出现红色或暗红色斑，压之不褪色

D.皮肤出现红色或暗红色斑，愈后可有皮肤脱屑

E.皮肤出现红色或暗红色斑，压之褪色