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下面各小数中,小数点后的“0”去掉后大小不变的数是(    )。
A . 0.07 B . 45.80 C . 0.501
如图是科学防控新冠肺炎病毒传染的宣传图片,图片上有图案和文字说明,其中图案是轴对称图形的是(   )
A . 打喷嚏捂口鼻 B . 喷嚏后慎揉眼 C . 勤洗手勤通风 D . 戴口罩讲卫生
下图“中国沿40°N附近局部地形剖面图”,若B为太行山,A地形区为(    )

A . 青藏高原 B . 内蒙古高原 C . 黄土高原 D . 四川盆地
解下列关于x的方程.
  1. (1) a2x+x=1;
  2. (2) b(x+3)=4.
如图所示电路,A、B为两个金属夹,分别在两金属夹之间接入硬币.铅笔芯.橡皮或塑料尺,闭合开关后观察小灯泡是否发光.在观察到小灯泡发光时,两金属夹之间接入的可能是(   )

A . 铅笔芯或硬币 B . 硬币或橡皮 C . 橡皮或塑料尺 D . 塑料尺或铅笔芯
新中国成立60年来,我国取得了一系列重大的科技成果,请按要求写出重大科技成果的名称。
(1)标志着我国跨入了世界核先进国家行列:  。
(2)我国开始跻身世界航天科技的大国之列:  。   
(3)探索生命奥秘具有重大理论意义的发明: 。   
(4)实现了水稻育种历史性突破的发明: 。

基因工程培育的“工程菌”通过发酵工程生产的产品,不包括(   )

A . 白细胞介素 B . 干扰素 C . 聚乙二醇 D . 重组乙肝疫苗
根据《关于推行地方各级政府工作部门权力消单制度的指导意见》,2015年底各省级政府、2016年底前市县两级政府,除保密事项外,要以清单形式将每项职权的名称、依据、行使主体、运行流程图和监督方式等,在政府网站等载体公布,我国政府向社会公布权力清单是(  )

①建设法治政府的基本要求

②促进公民对政府权力运行的法律监督

③纠正职责交叉重叠和“缺位”

④简政放权,优化权力运行,放置“越位”

A . ①② B . ①④ C . ②③ D . ③④

英国资产阶级革命过程中的反复和曲折说明了(   )

A . 人民群众没有积极参加 B . 资产阶级革命的历史条件没有成熟 C . 新的社会制度代替旧的社会制度需要长期激烈的斗争 D . 资产阶级和新贵族与封建王朝妥协
2019年7月6日,清华大学举行2019年研究生毕业典礼,清华大学校长邱勇在致辞中鼓励大家要在不断战胜困难和质疑的过程中坚定自信,他还希望同学们以开放自信的胸怀升华人生境界。这启示我们(    )
A . 自信是成功的唯一条件 B . 要充满自信,相信“天生我材必有用” C . 自信是避免困难的决定性因素 D . 有了自信,我们就能开创伟大而光荣的事业
选出拼写错误的一项(   )
A . class B . shop C . shcool
化学与社会发展、生产生活密切相关。
  1. (1) “沉睡三千年,一醒惊天下!”三星堆青铜器出土后立刻惊动了世界。青铜属于(填“复合”“有机高分子”或“金属”)材料。
  2. (2) 《汉代古火井碑序》记载:“诸葛丞相躬莅视察,改进技法,刳斑竹以导气(气指天然气),引井火以煮盐”,请用化学方程式表示天然气燃烧的原理
  3. (3) 食醋(含醋酸)、精盐(NaCl)、碱面(Na2CO3)、蔗糖(C12H22O11)都是厨房常备物品。用碱性溶液浸泡蔬菜可降低蔬菜残留农药的毒性,因此,在厨房中浸泡新鲜蔬菜时,可加入适量的。食用过量的醋会引起钙流失,青少年缺乏钙元素会导致病。
  4. (4) 对于二氧化碳的排放,我国提出力争于2030年前达到峰值,于2060年前实现碳中和。“碳捕捉与封存”是我国的一项先进技术,二氧化碳气体能被压缩是因为。被封存的二氧化碳有许多用途,请写出一条:
“84消毒液”的主要成分是NaClO,可通过氯气和氢氧化钠溶液反应制备,产物中还含有氯化钠和水。

  1. (1) 请写出上述反应的化学方程式
  2. (2) 如图所示,小金利用试管②制取“84消毒液”,夹子开始处于关闭状态,将液体滴入试管②充分反应后,打开夹子,可发现试管①内的水立刻沸腾。请解释“打开夹子,水立刻沸腾”的原因是:
阅读下面短文,从短文后各题所给的四个选项(A、B、C、D)中,选出可以填入空白处的最佳选项。

    As a kid, I loved everything about school. I loved books,1, tests and homework. Most of all I longed to someday march down the aisle (通道) to receive my2.That seemed more attractive even than getting married. But at 15, I had to3because my parents couldn't4my school education. My hope of getting a diploma was dead.

    Pretty soon, I married. I had three children, and I thought: "There5my diploma."

    Even so, I wanted my children to be educated. But Linda, our youngest child, had juvenile arthritis (幼年型关节炎) in her6and knees, which made it7for her to function (活动) in a normal classroom.

    One day, I saw an ad in the newspaper for evening courses.

    "That's the answer," I said to myself. Linda always felt8in the evening, so I would just sign her up for night schoo1.

    Linda was busy9out enrollment (入学) forms when the secretary said, "Mrs. Schantz, why don't you come back to10?"

    I 11, “There's no way! I'm 55!”

    12 he insisted, and before I knew what I had done, I was enrolled for classes in English and crafts. “This is only an experiment,” I 13 him, but he just smiled. To my surprise, both Linda and I thrived (茁壮成长) in evening school. I went back again the next semester, and my grades 14 improved.

    It was 15 going to school again, but it was no game. Sitting in a class full of kids was embarrassing, 16 most of them were respectful and encouraging. During the day, I still had loads of housework to do. But when I was down, Linda encouraged me. “Mom, you can't 17 now!” And when she was down, I 18her. Together we saw it through. At last, I got my diploma. 19 , my classmates all voted for me to be class speaker, and I got a $ 3, 000 college scholarship.

    Yes, Mom, I was late for school, but I got there 20 .

(1)
A . parents B . teachers C . trees D . flowers
(2)
A . job B . present C . prize D . diploma
(3)
A . drop out B . watch out C . keep out D . find out
(4)
A . cost B . afford C . spend D . buy
(5)
A . exists B . comes C . goes D . lies
(6)
A . hands B . head C . throat D . stomach
(7)
A . 1ikely B . convenient C . awful D . impossible
(8)
A . worse B . excited C . better D . exhausted
(9)
A . filling B . giving C . taking D . sending
(10)
A . work B . school C . home D . office
(11)
A . 1aughed B . told C . cried D . shouted
(12)
A . And B . But C . Although D . So
(13)
A . informed B . asked C . comforted D . warned
(14)
A . regularly B . rarely C . gradually D . normally
(15)
A . frightening B . moving C . amusing D . exciting
(16)
A . as if B . even if C . in case D . if only
(17)
A . continue B . rest C . abandon D . hesitate
(18)
A . distracted B . discouraged C . cheered D . defeated
(19)
A . To my surprise B . To my satisfaction C . To my regret D . To my horror
(20)
A . completely B . frequently C . immediately D . finally
已知椭圆C: 的左、右顶点分别为A,B,F为椭圆C的右焦点,圆x2+y2=4上有一动点P,P不同于A,B两点,直线PA与椭圆C交于点Q,则 的取值范围是(   )
A . (﹣∞,﹣ )∪(0, B . (﹣∞,0)∪(0, )   C . (﹣∞,﹣1)∪(0,1) D . (﹣∞,0)∪(0,1)
命题“ ”的否定是(    )
A . B . C . D .
I can teach you to swim.                    season:
已知平行直线l1:x﹣2y﹣2=0,l2:2x﹣4y+1=0,则l1与l2之间的距离为
以下均为中学化学常见物质,存在如下转化关系(部分产物已省略).通常C为气体单质,G为紫黑色固体单质.实验室中,常用固体E在B的催化下加热制取气体单质H.

  1. (1) G的化学式;F的电子式
  2. (2) 反应①的离子方程式
  3. (3) 写出另外一种实验室制取H的化学方程式
  4. (4) D溶液中阳离子的焰色反应火焰呈色;可用试剂检验D溶液中大量存在的阴离子.
甲、乙两车分别从A、B两地同时出发,相向而行,经过2.5小时相遇,甲车每小时行a千米,乙车每小时行b千米,A、B两地相距千米。当a=45,b=60时,A、B两地相距千米。
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