come, I, my dream, believe, will, true
_______________________________________________.
生物体由小长大与图 8 中 abc 三种细胞变化过程有关,下列叙述: ①a 表示细胞的生长; ②b 表示细胞的分裂; ③b 过程中染色体的变化最为明显; ④c 过程的结果是形成了不同的器宫,其中正确的是( )
A . ②③④ B . ①③④ C . ①②④ D . ①②③
When watching the raising of the national flag, we should stand s________ with our backs.
如图所示,物体A在大小为10N的拉力F作用下,以0.3m/s 的速度向右匀速运动(不计细绳的摩擦及重力),若物体A与桌面间的摩擦力为6N,已知动滑轮重为1N,下列说法正确的是(g=10N/kg)( )
A.拉力F做功的功率是3W
B.物体B的质量是1.1 kg
C.物体B上升的速度是0.15 m/s
D.去掉F,物体A仍保持静止则物体B的重力可以增加到17N
某中学要从高一年级甲乙两个班级中选择一个班参加电视台组织的 “ 环保知识竞赛 ” ,该校对甲乙两班的参赛选手(每班 7 人)进行了一次环保知识测试,他们取得的成绩(满分 100 分)的茎叶图如图所示,其中甲班学生的平均分是 85 ,乙班学生成绩的中位数是 85 .
( 1 )求 的值;
( 2 )根据茎叶图,求甲乙两班同学方差的大小,并从统计学角度分析,该校应选择甲班还是乙班参赛.
注:一组数据的方差公式: ,其中平均数为:
下图人物是明末农民起义军的领袖。下面关于他的表述不正确的是
A.提出“均田免赋”的口号
B.攻入西安,建立大顺政权
C.攻入北京,推翻明王朝
D.统一女真各部,建立后金政权
下列各式中计算结果为的是( )
A. B.
C.
D.
解放战争时期的民谣唱道: “最后一碗米送去做军粮,最后一尺布送去做军装,最后一个亲骨肉送到战场上。”此歌谣场景出现的原因是
A . 颁布了《中国土地法大纲》 B . 打土豪,分田地,建立政权
C . 地主减租减息,农民交租交息 D . 彻底摧毁了封建土地制度
现代社会里,养狗成为一种“时尚”,但遛狗伤人事故也时有发生,超声驱狗器(如图所示为网上一款)应运而生。实验结果显示:对着狗一按开关,狗好像听到巨大的噪声而躲开,而旁边的人什么也没听见。以下分析正确的是( )
A. 人什么也没听见,是因为它发出声音的响度小
B. 人什么也没听见,是因为它发出声波的频率不在人耳能够感受的频率范围内
C. 人什么也没听见,是因为它发出的声音不是振动产生的
D. 人什么也没听见,是因为它发出的声波不能在空气中传播
“火星你好,中国来了!”5月15日7时18分,天问一号探测器成功着陆于火星乌托邦平原南部预选着陆区,中国成为第二个成功着陆火星的国家。成功的背后,凝结着中国航天人昼夜不息的攻坚克难、卓越创新。这说明( )
①科技创新需要有挑战权威的批判精神 ②科技创新是综合国力竞争的决定因素
③中国在航天科技领域已走在世界前列 ④中国航天取得的成就离不开实干精神
A . ①② B . ①③ C . ②④ D . ③④
(2019·邵阳)名著阅读。
“它的性情就和别的猛兽不同,凡捕食雀鼠总不肯一口咬死,定要尽情玩弄,放走,又捉住,又放走,直到玩厌了,这才吃下去,颇与人们幸灾乐祸慢慢地折磨弱者的坏牌气相同。
(1)这段文字出自鲁迅的《_________ ___》(作品名称)
(2)结合作品分析作者所表达的情感。
下列诗句中属于表达“喜”这种情绪的是( )
A.日暮乡关何处是,烟波江上使人愁 B.独在异乡为异客,每逢佳节倍思亲
C.白日放歌须纵酒,青春作伴好还乡 D.世事茫茫难预料,春愁黯黯独成眠
When you feel a sneeze (喷嚏) or cough coming on, covering your mouth prevents the spread of germs (细菌) . You probably knew that.
But how to cover your mouth is very important. You might use tissues (纸巾) , and put your used tissues into the bin. “If you don't have tissues, you should sneeze into your elbow, not your hand, even if you are used to doing that.” The doctors advised.
“If somebody sneezes into his hands, those germs will be passed on to other people, or other objects that people touch.” said Dr. Hill.
Germs are most commonly spread by sneezing and coughing. When they land on your hands, they are passed from hands to things like bills, door knobs (扶手) , lift buttons and other surfaces. At the same time, the people around you can touch them.
“The suggestion was taken seriously about 10 years ago. However, most people didn't pay much attention to it. That means the adults may have missed the advice. But children are often taught in school the right way to cough or sneeze.” Dr. Benjamin said.
To be clear, people can't keep away from all the risks in this way, but it's the best choice. At the same time, we'd better wear masks (口罩) and often wash our hands. “Hand washing is one of the most important things people can do to keep healthy.” Dr. Hill said.
根据短文内容,选出最佳选项。
1 . According to this passage, when sneezing or coughing, you'd better not ________.
A . sneeze into your elbow B . cover your mouth with tissues
C . use your hand to cover your mouth D . cover your mouth with your elbow
2 . If you sneeze into hands, germs can spread through the following activities except ________.
A . using lift buttons B . using door knobs C . shaking hands D . washing hands
3 . Which is true according to the passage?
A . If you don't have tissues, you should sneeze into your hand.
B . The adult may be used to sneezing into their elbow.
C . Parents often teach their children the right way to cough or sneeze.
D . Wearing masks is a good way to keep away from germs.
4 . What's the main purpose of this article?
A . To tell us the correct way to use tissues when sneezing or coughing.
B . To tell us some correct ways to prevent the spread of germs.
C . To tell us it's necessary to sneeze or cough into elbow.
D . To tell us how to keep away from all risks.
5 . In which layout (版面) of the newspaper can we find this kind of passage?
A . Health. B . Sports. C . Business. D . Education.
(3+
)(3
﹣
)=_____.
时,将等质量的
分别加入到各盛有
水的两个烧杯中,充分搅拌后恢复到
,现象如图1、2所示。下列说法正确的是()
A. 甲中加入的固体是
B. 甲中溶液可能是该溶质的饱和溶液,乙中上层清液一定是该溶质的饱和溶液
C. 将甲、乙中的物质混合,充分搅拌,一定有固体剩余
D. 若将甲、乙的温度从升高到
,两溶液中的溶质质量分数相等