What is the main gas in the air we breathe? A. Oxygen B. Nitrogen C. Carbon dioxide D. Hydrogen 相关知识点: 试题来源: 解析 B。我们呼吸的空气中主要气体是氮气。A 选项氧气是维持生命所必需的,但不是空气中的主要气体;C 选项二氧化碳含量较少;D 选项氢气在空气中含量极少。本题考查空气的成分。
The air we breathe is a mixture of gases. What is air? A. A liquid B. A gas C. A solid D. A powder 相关知识点: 试题来源: 解析 B。我们呼吸的空气是气体的混合物。选项 A 液体错误;选项 C 固体错误;选项 D 粉末错误。反馈 收藏 ...
air为先行词,逗号后面的为非限制性定语从句,从句中breathe缺少宾语,所以答案为关系代词。what不能引导定语从句;when作为关系副词在句中做状语;that不能引导定语从句;which是关系代词,能引导限制性和非限制性定语从句。故选B。 结果一 题目 Air,___ we breathe every day, is necessary to life.A.whatB.whichC...
Now, don’t be mistaken. There are other greenhouse gases (nitrogen, methane, and even water vapor) that we could spend time focusing on too, but let’s just stick to carbon right now. What can we do? It’s no secret that lowering levels of atmospheric carbon is a *hot* topic (pun...
The air we breathe is polluted. What can we do to improve air quality? A. Burn more fossil fuels. B. Plant fewer trees. C. Use more cars. D. Ride bikes or walk. 相关知识点: 试题来源: 解析 D。为了改善空气质量,我们可以骑自行车或步行。A 选项燃烧更多化石燃料会加重污染;B 选项种更...
Acrolein is considered as the one of hazardous chemical that comes from the products of combustion. Many hazardous chemicals that belong to the special class of smelly compounds including aldehydes, formaldehyde and etaldehyde are identified as priority hazards. Moreover, the radioactive gas radon ...
百度试题 结果1 题目It is the bacteriahave generated the oxygen we breathe on earth.A. whatB. thatC. whereD. as 相关知识点: 试题来源: 解析 B 反馈 收藏
Why not go and in HappyValley? 82.树可以释放氧气给我们呼吸。 Trees canoxygen for us to breathe. 83.一些恐龙温顺,另一些恐龙凶猛Some dinosaurs were. Others were. 84.就在那时,一名消防员出现了。 At that time, a fireman. 85.我们可以把电变成不同形式的能量。 We canelectri...
The Earth's atmosphere is as large as it is invisible. A huge bubble of gases surrounds the Earth that humans and animals rely on to stay alive, but do not see or interact with consciously. Despite this invisibility, there's a lot more to the Earth's atmosphere than just oxygen. It'...
Chemistry is the study of matter and how it changes. Matter is everything that has mass and takes up space, like the air we breathe, the water we drink, and the objects we use every day. Chemistry helps us understand what things are made of and how they interact with each other. ...