统计分组的基本原则是必须保证在某一标志上组内各单位的（）。 A.差异性 B.结构性

一个圆柱的表面积是188.4厘米²，底面半径是5厘米，它的高是多少厘米？

两条直线相交，形成4个角，其中一个角是直角，这两条直线是______的关系．

Anyone who doubts that children are born with a healthy amount of ambition need spend only a few minutes with a baby eagerly learning to walk or a headp toddler starting to talk. No matter how many times the little ones stumble in their initial efforts, most keep on trying, determined to master their amazing new skill. It is only several years later, around the start of middle or junior high school, many psychologists and teachers agree, that a good number of kids seem to lose their natural drive to succeed and end up joining the ranks of underachievers. For the parents of such kids, whose own ambition is often inseparately tied to their children’s success, it can be a bewildering, painful experience. So it is no wonder some parents find themselves hoping that ambition can be taught like any other subject at school.
It’s not quite that simple. "Kids can be given the opportunities, but they can’t be forced," says Jaequelynne Eccles, a psychology professor at the University of Michigan who led a study examining what motivated first-and-seventh-graders in three school districts. Even so, a growing number of educators and psychologists do believe it is possible to unearth ambition in students who don’t seem to have much. They say that by instilling confidence, encouraging some risk taking, being accepting of failure and expanding the areas in which children may be successful, both parents and teachers can reignite that innate desire to achieve.
Dubbed Brainology, the unorthodox approach uses basic neuroscience to teach kids how the brain works and how it can continue to develop throughout life. The message is that everything is within the kids’ control, that their intelligence is

malleable

.
Some experts say our education system, with its p emphasis on testing and rigid separation of students into different levels of ability, also bears blame for the disappearance of drive in some kids. Some educators say it’s important to expose kids to a world beyond homework and tests, through volunteer work, sports, hobbies and other extracurricular activities. "The crux of the issue is that many students experience education as irrelevant to their life goals and ambitions," says Michael Nakkula, a Harvard education professor who runs a Boston-area mentoring program called Project IF (Inventing the Future), which works to get low-income underachievers in touch with their aspirations. The key to getting kids to aim higher at school is to tell them the notion that classwork is irrelevant is not true, to show them how doing well at school can actually help them fulfill their dreams beyond it. Like any ambitious toddler, they need to understand that they have to learn to walk before they can run.

The word "unearth" underlined in Paragraph 2 is closest in meaning to ______.

A．discover

B．seek

C．pursuit

D．analyze

公民、法人或者其他组织向行政机关申请复议的，复议机关应当在收到申请书之日起多少天内做出决定（法律、法规另有规定的除外）（）。

A.15天

B.1个月

C.2个月

D.3个月

E.6个月

测量SF6气体微水量，在（）情况下不宜进行。

A.在充气后

B.在温度低

C.早晨

D.中午