身高相同的甲、乙、丙三位同学星期天到野外去比赛放风筝,看谁放得高.甲、乙、丙放出

题型:解答题

问题:

身高相同的甲、乙、丙三位同学星期天到野外去比赛放风筝,看谁放得高.甲、乙、丙放出的线长分别为300m,250m,200m,线与地平面的夹角分别为30°,45°,60°.假设风筝线是拉直的,请你给三位同学打一下分数.

考点:解直角三角形
题型:解答题

在实验室配制100g10%的氯化铵溶液并探究酸碱性强弱与浓度及温度的关系.请回答有关问题:

①计算:需氯化铵的质量______g,水______mL;

②称量:用电子天平称取所需的氯化铵,用______(选填“50mL”、“100mL”或“200mL”)的量筒量取所需水的体积;

③溶解:将上述称量好的氯化铵和水放到烧杯中,用玻璃棒搅拌,其作用是______.

④反思:若称取的氯化铵中含有水分或其它杂质,则所配制的氯化铵溶液的溶质质量分数会______.(选填“偏大”、“不变”或“偏小”)

⑤测溶液的酸碱性:用pH试纸测得氯化铵溶液的pH为5,则其为______性.为进一步探究其酸碱性的强弱与溶液的浓度、温度是否有关,采用以下四个步骤研究.请完成第二、第三步实验步骤.(不必写实验中涉及的仪器)

第一步:分别配制溶质质量分数为5%、10%、20%的氯化铵溶液;

第二步:在相同______下;分别测5%、10%、20%的氯化铵溶液的pH;

第三步:______;

第四步:根据测得数据,综合分析得出氯化铵溶液酸碱性的强弱与浓度、温度关系.

题型:解答题

观察、分析实验现象,可以帮助我们理解科学的本质,下列现象描述与事实不相符的是[ ]

A.铁丝在氧气中剧烈燃烧,火星四射,生成黑色固体,放出大量的热

B.把燃着的木条放在盛满二氧化碳的集气瓶口,木条熄灭

C.硫酸铜溶液与氢氧化钠溶液混合,生成蓝色沉淀

D.加热氯化铵与氢氧化钠固体混合物,生成能使湿润蓝色石蕊试纸变红色的气体

题型:解答题

阅读理解。

     The latest research suggests that the key factor separating geniuses from the merely accomplished is not

I.Q., a generally bad predictor of success. Instead, it's purposeful practice. Top performers spend more hours

practising their craft. It you wanted to picture how a typical genius might develop, you'd take a girl who

possessed a slightly above average language ability. It wouldn't have to be a big talent, just enough so that she

might gain some sense of distinction. Then you would want her to meet, say, a novelist, who coincidentally

shared some similar qualities. Maybe the writer was from the same town, had the same family background,

or shared the same birthday.

     This contact would give the girl a vision of her future self. It would hive her some idea of a fascinating

circle who might someday join. It would also help if one of her parents died when she was 12, giving her a

strong sense of insecurity and fuelling a desperate need for success. Armed with this ambition, she would

read novels and life stories of writers without end. This would give her a primary knowledge of her field.

She's be able to see new writing in deeper ways and quickly understand its inner workings.

     Then she would practise writing. Her practice would be slow, painstaking and error-focused. By practising

in this way, he delays the automatizing process. Her mind wants to turn conscious, newly learned skills into

unconscious. Automatically performed skills. By practising slowly, by breaking skills down into tiny parts and

repeating, she forces the brain to internalize a better pattern of performance. Then she would find an adviser

who would provide a constant stream of feedback, viewing her performance form the outside, correcting the

smallest errors, pushing her to take on tougher challenges. By now she is redoing problems-how do I get

characters into a room-dozens and dozens of times. She is establishing habits of thought she can call upon in

order to understand or solve future problems.

     The primary quality our young writer possesses is not some mysterious genius. It's the ability to develop

a purposeful, laborious and boring practice routine; the latest research takes some of the magic out of great

achievement. But it underlines a fact that is often neglected. Public discussion is affected by genetics and

what we're "hard-wired" to do. And it's true that genes play a role in our capabilities. But the brain is also

very plastic. We construct ourselves through behaviour.

1. The passage mainly deals with _____.

A. the function of I.Q. in cultivating a writer

B. the relationship between genius and success

C. the decisive factor in making a genius

D. the way of gaining some sense of distinction

2. By reading novels and writers' stories, the girl could _____.

A. come to understand the inner structure of writing

B. join a fascinating circle of writers someday

C. share with a novelist her likes and dislikes

D. learn from the living examples to establish a sense of security

3. In the girl's long painstaking training process, _____.

A. her adviser forms a primary challenging force to her success

B. her writing turns into an automatic pattern of performance

C. she acquires the magic of some great achievement

D. she comes to realize she is "hard-wired" to write

4. What can be concluded from the passage?

A. A fuelling ambition plays a leading role in one's success.

B. A responsible adviser is more important than the knowledge of writing.

C. As to the growth of a genius, I.Q. Doesn't matter, but just his|her effort.

D. What really matters is what you do rather than who you are.

题型:解答题

立体防御战略

题型:解答题

政治思想家总结的驯服国家的必要事物是()。

A.明确的社会阶层体系

B.清晰的规则的建立

C.能够使权力在许多力量群体中广泛分布的结构

D.合理的利益分配机制

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