题海网，海量题库；找题库、找试卷、找答案就上题海网。

区别氢气、氧气、空气和二氧化碳四瓶无色气体最简单的方法是(   )

正方形的面积S与边a之间的关系式为，其中变量是．

我国面积最大的省级行政区是（    ）

“春秋之初，楚国是中原诸侯国里的南方蛮夷……到楚庄王时期，楚国文化潜移默化地成为华夏文化的一部分……楚人已经完全接受了中原文化，与中原人无异。”以上说明春秋时期的争霸战争（    ）

历史知识需要去伪存真。辨别下列史实的正误，用“正确”“错误”表示，并加以改正。

下列生物中，都属于原核生物的一组是（    ）

①噬菌体  ②蓝藻  ③酵母菌  ④乳酸菌 ⑤支原体  ⑥水绵  ⑦小球藻  ⑧葡萄球菌 ⑨发菜  ⑩青霉菌

一辆汽车从静止开始做匀加速直线运动,已知途中先后经过相距27m的A、B两点所用时间为2s,汽车经过B点时的速度为15m/s。求：

找出错误并改正

I couldn't buy anything because I leave my wallet at home just now._

阅读下面的材料，根据要求写作。

今年两会期间，全国政协委员、江苏省锡山高级中学校长唐江澎在“委员通道”上的一席话刷屏全网，引发热议。唐校长表示，好的教育应该是培养终身运动者、责任担当者、问题解决者和优雅生活者。

唐校长的话引发了你怎样的联想、思考和感悟？请你结合自己受教育的经历，就其中体会最深的一点写一篇文章。

要求：结合材料，确定立意，自定文体，自拟标题；切合身份，贴合主题，不要套作，不得抄袭；不得泄露个人信息；不少于800字。

古希腊哲学家伊壁鸠鲁说：“当一个人年轻的时候，不要让他耽误了哲学研究，当他年老的时候，也不要让他对他的研究发生厌倦，因为要获得灵魂的健康，谁也不会有太早或太晚的问题。说哲学研究的时间还没有到或已经晚了，就像说享福的时间还没有到或已经晚了一样。”伊壁鸠鲁把学习哲学和灵魂的健康、人生的幸福联系在一起，是因为（    ）

①哲学为人们认识和改造世界提供根本观点和方法

②哲学告诉人们认识和改造世界的具体知识和方法

③哲学为人们提供世界观、人生观和价值观指导

④哲学以认识世界为目的，让人们不断感悟真理

中华民族有着悠久的文明历史，我国古代早就有人对自然现象进行观察和研究，留下了许多史料记载。 下列有关记载和相应物理本质的解释，其中不正确的是（     ）

进入新环境，遵守新规则（    ）

Bill, I planned to give you the card on Saturday, but I ________ forgot.

阅读理解

    In 2019, Alipay Ant Forest was awarded(奖励) the United Nation's highest environmental honor – the "UN Champions of the Earth" award – for encouraging over half a billion people to take action in their daily lives to live greener lifestyles and help protect the environment with digital(数码) technology.

    Ant Forest is an app-based game that is sweeping across China. The users of the game get green energy points for choosing low-carbon(低碳) activities like taking a bus or using less plastic. Once players have gotten enough green energy, they can plant a virtual(虚拟的) tree in Ant Forest. For every tree planted in the virtual game, a real tree is planted by Ant Forest in China's countryside. Ant Forest says 100 million real trees have been planted so far, covering a total area of 933 square kilometers — almost the size of 130,000 soccer fields.

    In order to make it possible for more than 500 million users to watch their trees growing, Ant Forest works with GaGo Group to monitor trees using satellites(卫星). Two satellites took pictures of the desert areas before and after the tree planting to show users how their everyday actions have made a difference.

    Alipay Ant Forest shows how technology can change our world. Internet connects the virtual world with the real world. This has been easily accepted by the Chinese youth. Alipay Ant Forest's popularity shows that the public is ready to take action to protect our living environment. Many Chinese net users said that they were so proud that they had made a contribution to the greening of the world through online games.

填上＞或＜．

590905

400399

你可以尝试去读一下这本书。

You can this book

When scientists i_ the bones, they were surprised to find that these dinosaurs could not only run like the others but also climb trees.

下列关于信息特征的叙述，错误的是（  ）

已知i为虚部单位，若复数的实部与虚部互为相反数，则．