导火索的火焰顺着导火索燃烧的速度是0.8 cm/s,为了使点火人在导火索火焰烧到

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问题:

导火索的火焰顺着导火索燃烧的速度是0.8 cm/s,为了使点火人在导火索火焰烧到爆炸物以前能够跑到离点火处120 m远的安全地方去,导火索需要___________米才行。(假设人跑的速率是4 m/s)

考点:匀速直线运动
题型:填空题
制印刷电路时常用FeCl3溶液作为“腐蚀液”,发生的反应为:2FeCl3+Cu=2FeCl2+CuCl2向盛有FeCl3溶液的烧杯中加入铁粉和铜粉,反应结束后,下列结果不可能出现的是(  )

A.有Cu无Fe

B.有Fe无Cu

C.Fe、Cu都有

D.Fe、Cu都无

题型:填空题

欲观察病变的微细结构,应采用的扫描方式是()

A.间隔扫描

B.动态扫描

C.快速扫描

D.标准全周扫描

E.超薄层扫描

题型:填空题

下列有关人的生殖和发育的叙述中,正确的是

A.受精作用发生在女性子宫内

B.睾丸是男性性腺,分泌雌性激素

C.胎儿通过脐带与母体完成物质交换

D.青春期发育的突出特征是生殖器官的发育和成熟

题型:填空题

[听力原文] 女:明天我们去玩儿玩儿吧,你已经忙了一个月了。 男:是该放松放松了。 问:男的是什么意思?()

A.太忙了 

B.很放松 

C.忙完了 

D.该去玩儿玩儿

题型:填空题

There is an ever-widening gap between black male college enrollees and their female and white counterparts, says the American Council on Education (ACE).
Twenty years ago, according to ACE’s "Annual Status Report on Minorities in Higher Education," 30 percent of African American male high school graduates (ages 18 to 24) were enrolled in college, compared with 28 percent of same-age black females and 41 percent of white males.
Now, some 37 percent of black men are enrolled, compared with 42 percent of African American women and 44.5 percent of white males. So while there are more black males enrolling in college today than 20 years ago, other groups have outstripped them in enrolling and, even more importantly, in retention rates.
The graduation rate of black men is lower than that of any group. Only 35 percent of black males enrollees graduated within six years from colleges in 1996, compared with 59 percent of white males, 46 percent of Hispanic men, 41 percent of American Indian males and 45 percent of the black women who entered the same year.
Surveys and reports are hinting that the country’s educational apparatus is stacked against the black male. Fewer than one in five students of color have graduated from high school, have a set of college-prep courses on their high school transcripts and "demonstrate basic literacy" -- the necessities for being "college ready."
Another glaring problem is that black males are disproportionately labeled as discipline and behavioral problems and fast tracked out of high schools through expulsions and suspensions.
As if that’s not enough, says ACE’s William Harvey, there’s a virtual drying up of federal aid-to-education grant money coupled with jacked-up tuitions, which make it necessary for low-income students to assume an average $ 20,000 debt to finish a four-year curriculum.
"For those in the lower economic category, the availability of financial aid determines who gets to go to college and who doesn’t," observes Harvey.
Harvey points out that, over the years, federal funding has undergone a "complete reversal," from "a 70 percent to 30 percent grant-to-loan ratio 20 years ago" to the exact opposite today.
"An 18-year-old male will be more inclined to say, ’I want money in my pocket now’ and attempt to get a job," adds Harvey. "But many take on the debt, become part-time students, work 20-plus hours a week and become five-year students at a four-year college."
The inequity of that educational apparatus is especially clear when you look at the black males who persevere -- those who go on to finish high school, earn a bachelor’s degree and even finish grad school.
A recently released Census report shows that, whether they have a high school diploma or a master’s degree, black men will earn roughly 25 percent less than Whites.

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