石墨的多型变体有（）。

[问答题]Directions:In this section, there is one passage followed by 5 questions. Read the passage carefully, then answer the questions in a maximum of 10 words. Remember to write the answers on the Answer Sheet.　　High Dropout Rate in US　　Many young people in the United States never finish high school. Exactly how many dropouts is another issue. Recent studies of dropout rates have had conflicting results. For one thing, schools define and measure their dropout rates differently.　　Some researchers say about fifteen to twenty parents of public school students do not complete their education. But many other experts and policymakers believe that for the past twenty years, the dropout rate has been around thirty percent. For Latino and black students, the numbers are even higher. Researchers say almost half of them leave school.　　At the same time, almost half the states let students leave school before the age of eighteen without informing their parents.　　Finding a good job without a high school education is more and more difficult. A Northeastern University study in 2002 found that almost half of all dropouts aged sixteen to twenty-four did not have a job.　　The lack of high school education can also lead to other problems. An estimated two-thirds of prisoners in the United States dropped out of high school.　　Recent studies have shown that the majority of students who drop out do not do it because they are failing. Many are bored with their classes or feel disconnected from their school and teachers. Some students feel that educators place low expectations on them. Teen pregnancies also add to the dropout problem.　　During the past twenty years, there have been efforts to increase graduation rate through education reforms. Some communities are working on dropout prevention programs. These include alternative high schools to meet special needs.　　Some programs, for example, provide free transportation and childcare to help young mothers and fathers finish school. Yet special programs can cost a lot, and many school systems have limited budgets.　　Federal spending on second-chance programs to help students finish school has decreased from the 1970s. This was shown in a report last year from the Educational Testing Service.　　Experts suggest "early warning systems" to help identify young schoolchildren at risk of dropping out of high school. They say schools also need to get parents more involved, especially if their children are missing school often.　　Questions:　　1．What is the researchers’ estimated percentage of school dropouts among Latino and black students?　　2．What efforts have been made to increase graduation rates?　　3．What has been done to help young parents complete their education?　　4．Who made a report about the decrease，of Federal spending on second-chance programs to help students finish school?　　5．What do experts suggest setting up to help prevent students from dropping out of school?

[单选题]具有抗炎作用的他汀类调血脂药（　　）。

[问答题]在涉外经济中，如何坚持平等互利原则

[单选题]按照《施工现场临时用电安全技术规范》（JGJ46-2005）的规定，施工现场内使用行灯的电源电压应不大于（）。

[单选题]关于外科营养，正确的是（　　）。

[多选题]下列关于饭店火警处理的表述正确的有（）。

[单选题]最早的境外货币被称之为（）。

[单选题]JT-C系列机车信号接线盒的输入电压范围为（）。

[单选题]“自然科学的独立宣言”指的是（）。

[单选题]东亚银行母行在（）。

[多选题]石墨的多型变体有（）。

[问答题]什么是易石墨化炭和难石墨化炭？

[问答题]什么是石墨化和石墨化过程？石墨化的目的是什么？

[问答题]什么是石墨单晶、石墨多晶体和石墨微晶？

[单选题]石墨属于（）。

[名词解释题]石墨垫

[名词解释题]石墨化

[名词解释题]石墨化

[名词解释题]石墨

[名词解释题]钢的石墨化