下列属于预防成本的是( )A．复检和筛选费 B．质量评审费 C．进货测试费 D．质

在实验室里，同学们做氧气的制取、性质的分组实验，实验中各小组要消耗两瓶氧气．经计算这两瓶氧气在通常状况下的质量共约为0.72g，若要用10%的过氧化氢溶液和MnO₂来制取氧气：

（1）至少需要向每个实验小组提供该溶液多少克？

（2）实验准备室中有下列仪器，为保证同学们安全顺利地制取氧气，应选择的仪器有______（写序号）提示：10%过氧化氢溶液的密度为1.04g/cm³．

维修电工班组主要是为生产服务的。

阅读理解。

     The campaign is over. The celebrations have ended. And the work for US president-elect Barack Obama

has begun.

     The 47-year-old politician rose to the highest post because of his stand against the war in Iraq and his plans

to fix a weak economy. But what will the first 47-year-old African-American president do for race relations?

     Obama's victory appears to have given blacks and other minorities a true national role model. For years,

many looked to athletes and musicians for inspiration. As Darius Turner, an African-American high school

student in Los Angeles, told the Los Angeles Times, "Kobe doesn't have to be everybody's role model

anymore."

     Recent polls (民意测验) also suggest that Obama's victory has given Americans new optimism about race

relations. For example, a USA Today poll found that two-thirds of Americans believe relations between blacks

and whites "will finally be worked out". This is the most hopeful response since the question was first asked

during the civil rights revolution in 1963.

     However, it's still too early to tell whether Obama's presidency will begin to solve many of the social problems facing low-income black communities.

     Although blacks make up only 13 percent of the US population, 55 percent of all prisoners are

African-American. Such numbers can be blamed on any number of factors on America's racist past, a failure

of government policy and the collapse (瓦解) of the family unit in black communities.

     It is unlikely that Obama will be able to reverse (扭转) such trends overnight. However, Bill Bank, an expert

of African-American Studies, says that eventually young blacks need to find role models in their own

communities."That's not Martin Luther King, and not Barack Obama," he told the Los Angeles Times."It's

actually the people closest to them. Barack only has so much influence."

      In the opinion of black British politician Trevor Phillips, Obama's rise will contribute more to

multiculturalism than to race relations in the US.

      "When the G8 meets, the four most important people in the room will be the president of China, the prime

minister of India, the prime minister of Japan and Barak Obama," he told London's The Times newspaper."It

will be the first time we've seen that on our television screens. That will be a huge psychological shift (心理转变) for both the white people and the colored ones in the world."

1. For years, before Obama was elected president of the US, _______.

A. Kobe was the only role model for all the blacks

B. blacks could only find role models on the basketball court

C. minorities in America couldn't find role models in their real life

D. American blacks had no role model who was successful in political area

2. According to Bill Bank, ________.

A. it's better for young blacks to find role models in those who are close to them

B. young blacks should not be so much influenced by Obama

C. blacks should find other role models because Obama is far from their reality

D. Obama is not the proper role model for African-Americans

3. What would be the best title for this passage?

A. The First African-American President

B. America's New Role Model

C. Obama- A Successful Black.

D. Choosing a Right Role Model

4. What will be the huge psychological shift Trevor mentioned at the end of the passage?

A. The other three leaders all support Obama.

B. Obama is an African-American president.

C. None of the four leaders is white.

D. The other three leaders except Obama are from Asian countries.

关于咬肌间隙感染下列说法错误的是（）。

A.感染多来自于下磨牙冠周炎和根尖周炎

B.临床表现为下颌角区红肿痛

C.常伴张口困难

D.脓肿形成后常在下颌升支外侧触及波动感

E.切开引流时作位于下颌角下缘下1～2cm的弧形切口

我国生产的银河系列计算机属于（）。