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下列选项中,对汉字的演变过程理解有误的一项是(    )
A . 甲骨文是刻在龟甲或兽骨上的文字,主要在商周时期使用 B . 金文是铸刻在青铜器上的文字,主要在汉代使用。 C . 小篆是从战国时期的秦国文字发展而来的,秦统一全国后得到推行,成为我国最早的统一的文字。 D . 进入南北朝之后,楷书成为占主导地位的字体,一直通行至今。
下列句子中,标点符号的使用正确的一项是()

A . 同时,在产品的包装上、商标上、说明书的文字、图片上讲究精美,也是必要的。 B . 这位老“巴尔干”同意本报记者的看法:即协议虽签,维和部队开始“维和”,但科索沃的危机并没有消除。 C . 《中华人民共和国经济合同法》规定:“经济合同是法人之间为实现一定经济目的,明确相互义务关系的协议。” D . 杨绛的《记钱钟书与围城》,给我们详尽地介绍了《围城》这部令人拍案叫绝的杰作是如何创作出来的?
已知方程x2+(a﹣3)x+3=0在实数范围内恒有解,并且恰有一个解大于1小于2,a的取值范围是
—What were you doing this time yesterday?
—I ________ my homework at John's house.

A . do B . am doing C . did D . was doing
小丽这样认知自己:在家中是父母的孩子,在学校是老师的学生,在小区是业主,在电影院是观众……这表明(    )
A . 人的身份是在社会关系中确定的 B . 随着身体的成长,我们的社会空间不断延展 C . 在不同的社会关系中,我们具有相同的身份 D . 随着能力的提高,我们对生活的感受越来越丰富
阅读理解

People have many different ways to relax during break time at work or school. Smartphones are probably the number one choice for a quick mental vacation.

Although it might seem like a good time, looking at your cellphone may damage your mental power, according to a recent psychological study from Rutgers University in the United States. For the study, more than 400 students were asked to finish a set of 20 word puzzles. Halfway through the task, the students were divided into three groups. One group was allowed to take a break and use cellphones to buy things online. The second group was asked to have a rest and buy things using a computer. The last group didn't have a break at all.

Interestingly, the group that used their cellphones during the break went back to work feeling the most tired and least motivated to continue. They also had the hardest time solving the remaining word puzzles. The cellphone group took 19 percent longer to finish the rest of the task, and solved 22 percent fewer problems than those in the other break conditions combined.

Terri Kurtzberg, co-author of the study, explained that they assumed looking at cellphones during a break would be no different from any other break—but instead, the phone may cause increasing levels of distractions (分心) that make it difficult to return focused attention to work tasks. "Cellphones may have this effect because even just seeing your phone activates thoughts of checking messages, connecting with people, access to ever-refilling information and more, in ways that are different from how we use other screens like computers, and laptops," Kurtzberg told Science Daily. This is echoed (呼应)by a 2017 study from the US University of Chicago. It found that even if cellphones are turned off or turned face down, their mere presence reduces a person's cognitive capability  (认知能力).

So, during your next break, try putting your smartphone away. Go out for a walk, get to know your classmates or even take a nap. You may be surprised by the result!

  1. (1) What did the study find about using cellphones during breaks?
    A . It could ensure people a good time at work. B . It could reduce one's ability to solve problems. C . It could benefit people both, physically and mentally. D . It could end up damaging one's magic power.
  2. (2) Which of the following statements is TRUE according to the passage?
    A . The study could be traced back to as early as 2017. B . Terri Kurtzberg was one of the authors of the study. C . Participants were divided into three groups in the first place. D . The study was designed to solve a set of20 word puzzles.
  3. (3) What can we learn about cellphones from Kurtz-berg's words?
    A . They have become a significant part of people's lives. B . They have improved people's ability to process information. C . They may influence people in the same way as computers do. D . They may make it harder for people to stay concentrated at work.
  4. (4) What does the author suggest people do during break time?
    A . Turn off their cellphones. B . Keep their cellphones face down. C . Replace cellphones with laptops. D . Keep their cellphones out of sight.

 如图为甲、乙、丙三种物质的溶解度曲线.

(1)图中A点表示的乙溶液为(填“饱和”或“不饱和”)溶液;

(2)t3℃时,将40g甲物质加入到50g水中,所得溶液溶质质量分数为 ;

(3)t3℃时,将等质量甲和丙的饱和溶液降温到t2℃,所得溶液质量大小关系为:甲丙(填“<”、“>”或“=”);

(4)将t1℃时丙的不饱和溶液变为饱和溶液可采取的方法为(填一种即可).


在集合 中各取一个数字组成一个两位数,则这个两位数能被4整除的概率为(    )
A . B . C . D .
  
  1. (1) + +
  2. (2)
填上正确的数字.
                              
  1. (1)
  2. (2)
下列各组物质,能在pH=1的溶液中大量共存,且形成无色溶液的是(   )
A . NaNO3HCl  Na2SO4   B . NaNO3 NaCl  CuSO4 C . NaCl  Na2SO4Na2CO3 D . NaOH   BaCl2 Na2SO4
听录音,选出你所听到的句子(   )
A . Good afternoon! B . Goodbye!
已知a2+3a=1,则代数式2a2+6a-1的值为(  )
A . 0 B . 1 C . 2 D . 3

如图,在平面直角坐标系中,▱ABCO的顶点A在x轴上,顶点B的坐标为(4,6).若直线y=kx+3k将▱ABCO分割成面积相等的两部分,则k的值是(   )

A . B . C . D .
人们要注意自己的,展示自己良好的形象。
What does the girl's sister do?
A . B . C .
如图,已知△ABC≌△AFE,若∠ACB=65°,则∠EAC=

炒菜时油锅着火,用锅盖盖灭,其灭火原理是(   )
A . 隔绝空气 B . 清除可燃物 C . 降低可燃物的着火点 D . 使可燃物温度降到着火点以下
Can you help them (find) the way?
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