题干

苯胺是橡胶助剂、医药磺胺药及生产农药的重要原料,苯胺的化学式为C6H5NH2.苯胺对环境有危害,对水体可造成污染,会引起人体高铁血红蛋白血症、溶血性贫血和肝、肾损害.请根据苯胺的化学式,回答下列问题:
(1)苯胺是由____种元素组成。
(2)苯胺中C、H、N元素的质量比____。
(3)苯胺中碳元素的质量分数是____(结果保留到0.1%)。

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3,72:7:14​,77.4%

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    Some students get so nervous before a test, they do poorly even if they know the material. Sian Beilock has studied these highly anxious test-takers.

    Sian Beilock: “They start worrying about the consequences. They might even start worrying about whether this exam is going to prevent them from getting into the college they want. And when we worry, it actually uses up attention and memory resources. I talk about it as your cognitive horsepower that you could otherwise be using to focus on the exam.”

    Professor Beilock and another researcher, Gerardo Ramirez, have developed a possible solution. Just before an exam, highly anxious test-takers spend ten minutes writing about their worries about the test.

    Sain Beilock: “What we think happens is when students put it down on paper, they think about the worst that could happen and they reappraise the situation. They might realize it's not as bad as they might think it was before and, in truth, it prevents these thoughts from appearing suddenly when they're actually taking a test.”

    The researchers tested the idea on a group of twenty anxious college students. They gave them two short math tests. After the first one, they asked the students to either sit quietly or write about their feelings about the upcoming second test.

    The researchers added to the pressure. They told the students that those who did well on the second test would get money. They also told them that their performance would affect other students as part of a team effort.

    Professor Beilock says those who sat quietly scored an average of twelve percent worse on the second test. But the students who had written about their fears improved their performance by an average of five percent.

    Next, the researchers used younger students in a biology class. They told them before final exams either to write about their feelings or to think about things unrelated to the test.

    Professor Beilock says highly anxious students who did the writing got an average grade of B+, compared to a B- for those who did not.

    Sain Beilock: “What we showed is that for students who are highly test-anxious, who'd done our writing intervention, all of a sudden there was no relationship between test anxiety and performance. Those students most prone to worry were performing just as well as their classmates who don't normally get nervous in these testing situations.”

    But what if students do not have a chance to write about their fears immediately before an exam or presentation? Professor Beilock says students can try it themselves at home or in the library and still improve their performance.

Title: Overcoming test ____

Problem

Some students get nervous before a test, so they can't do____even if they know the material.

Reason

____ about the consequences ____them their attention and memory resources.

Solution

Write down their worries to ____the negative thoughts appearing suddenly.

Results of the researches

College students:____ with those sitting quietly, students writing about their fears improved their performance.

Younger students: highly anxious students who did the writing instead of ____things unrelated to the test got ____grades.

____ ways to solve the problem

If students have no ____to write about their fears immediately, they can try it themselves at home or in the library.