25.如图.在△ABC中, D.E分别是AC.AB上的点, BD与CE交于点O. 给出下列三个条件:①∠EBO=∠DCO,②∠BEO=∠CDO,③BE=CD. (1)上述三个条件中, 哪两个条件可判定△ABC是等腰三角形, (2)选择第⑴小题中的一种情形, 证明△ABC是等腰三角形. 查看更多

 

题目列表(包括答案和解析)

如图,两木块的的质量分别是m1和 m2,两轻弹簧的劲度系数分别为k1和k2,上面的木块压上面的弹簧上,整个系处于平衡状态,现缓慢向上提上面的木块直到它刚离开上面的弹簧,在这个过程中,下面的木块移动的距离为:(   )

A.  B.  C.   D.

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(本题12分)根据空气质量指数API(为整数)的不同,可将空气质量分级如下表:

对某城市一年(365天)的空气质量进行监测,获得的API数据按照区间进行分组,得到频率分布直方图如图.                         

(1)求直方图中的值;

(2)计算一年中空气质量为良的天数;

(3)某环保部门准备在一年内随机到该城市考察两次空气质量,求两次考察空气质量都为良的概率(结果用分数表示).

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最近,校园安全成为人们广泛关注的话题,为确保师生安全,你校决定禁止外人进入校园。为此,学校在学生中做了一次“家长该不该进校园及其原因”的调查。调查结果如下图所示:

根据上图信息,请以“Should parents be banned from entering campus?”为题,用英语写一篇100-120个词的短文。要求如下:
1. 简要描述图中的信息(包括人数比率、观点及原因);2. 谈谈你的看法。
注意:文章的标题和开头已给出(不计词数)。
Should parents be banned from entering campus?
Recently, campus security has become a hot issue. To ensure security, strangers are banned from entering campus by our school, and a survey has been made among the students about whether parents should be included.

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Directions: Write an English composition in 120 - 150 words according to the instructions given below in Chinese.

最近某学校在学生中做了一次“有烦恼向谁说?”的调查,调查结果如图表示。请你简要描述调查结果,并谈谈你自己的想法。

I am a Senior Three student.Recently we have carried out a survey--"who to share my worry?" The main findings are as follows

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第二部分阅读理解(共20小题。每小题2分;满分40分)
第一节   阅读下列短文,从每题所给的四个选项(ABC和D)中,选出最佳选项,并在答题卡上将该项涂黒。
A
Long after the 1998 World Cup was won, disappointed fans were still cursing the disputed refereeing (裁判) decisions that denied victory to their team. A researcher was appointed to study the performance of some top referees.
The researcher organized an experimental tournament (锦标赛) involving four youth teams. Each match lasted an hour, divided into three periods of 20 minutes during which different referees were in charge.
Observers noted down the referees' errors, of which there were 61 over the tournament. Converted to a standard match of 90 minutes, each referee made almost 23 mistakes, a remarkably high number.  
The researcher then studied the videotapes to analyze the matches in detail. Surprisingly, he found that errors were more likely when the referees were close to the incident. When the officials got it right, they were, on average, 17 meters away from the action. The average distance in the case of errors was 12 meters. The research shows the optimum (最佳的) distance is about 20 meters.
There also seemed to be an optimum speed. Correct decisions came when the referees were moving at a speed of about 2 meters per second. The average speed for errors was 4 meters per second.
If FIFA, football's international ruling body, wants to improve the standard of refereeing at the next World Cup, it should encourage referees to keep their eyes on the action from a distance, rather than rushing to keep up with the ball, the researcher argues.
He also says that FIFA's insistence that referees should retire at age 45 may be misguided. If keeping up with the action is not so important, their physical condition is less critical.  
41. The number of refereeing errors in the experimental matches was _______.
A. slightly above average                            B. higher than in the 1998 World Cup
C. quite unexpected                                   D. as high as in a standard match
42. The findings of the experiment show that _______.
A. errors are more likely when a referee keeps close to the ball
B. the farther the referee is from the incident, the fewer the errors
C. the more slowly the referee runs, the more likely will errors occur
D. errors are less likely when a referee stays in one spot
43. The word "officials" (Line 2, Para. 4) most probably refers to _______.
A. the researchers involved in the experiment
B. the inspectors of the football tournament
C. the referees of the football tournament
D. the observers at the site of the experiment
44. What is one of the possible conclusions of the experiment?
A. The ideal retirement age for an experienced football referee is 45.
B. Age should not be the chief consideration in choosing a football referee.
C. A football referee should be as young and energetic as possible.
D. An experienced football referee can do well even when in poor physical                condition.

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