解析 A核心短语/词汇:help sb./ sth. (to) do sth. 帮助某人/某物做某事句子译文:氧气是唯一的助燃气体吗? 本题考查定语从句。___helps fire burn 用来修饰之前的名词gas, 该从句的引导词在定语从句中做主语,不能省略,先行词有only 修饰时不能用which; what 不能引导定语从句,故选项A符合题意。反馈...
What type of element is calcium? Calcium: Calcium is represented by Ca on the periodic table. Its atomic number is 20 and it is silvery gray in color. It is also found in limestone and fossilized remains. It was discovered and first isolated by Humphry Davy. ...
百度试题 题目What is the atomic number of oxygen?A、2B、6C、8D、20Answer:C 科目四考试网___科目四考试题库相关知识点: 试题来源: 解析 http://www.km4ks.com/st/tk/ 反馈 收藏
What type of element is zirconium? In other words, what is it classified as on the periodic table? What is the name of the Group 1 elements in the periodic table? An element in the lower-left corner of the periodic table: a. is either a metal or metalloid. b. is either a metalloid...
Kensal E. van HoldeSpringer Berlin HeidelbergDecker, H. & Van Holde, K., E. 2011, "Oxygen, Its Nature And Chemistry: What Is So Special About This Element?" in Oxygen and the evolution of life, Springer, Berlin; Heidelberg; New York, pp. 1-18....
A. Silicon atoms. B. Carbon atoms. C. Oxygen atoms. D. Hydrogen atoms. 相关知识点: 试题来源: 解析 B。解析:文章中明确提到“Graphene is an extremely thin and strong material. It is made up of a single layer of carbon atoms arranged in a hexagonal lattice.”,石墨烯是由一层碳原子组成...
To what category of elements does an element belong if it is a poor conductor of electricity? A. transition elements B. metalloids C. nonmetals D. metals Electrical Conductivity: For a substance to conduct electricity, it ...
Oxygen is a gaseous chemical element vital to respiration. Although pure oxygen is used medicinally, it can be dangerous when...
这个句子的主语是water,谓语是will continue to be,表语是what it is today,补语是next in importance to oxygen.what 在句子中表示"什么的样子"就像She is no longer what she was ten years ago.她不再是十年前的样子了.as 不能引导表语从句.而how 是作状语,表示怎样.which指哪一个,要在一定范围内. ...
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal,