We firmly believe that war never settles anything. It only _____ violence.

现代医学的药理研究表明，艾叶是一种广谱抗菌抗病毒的药物，它对多种病毒和细菌都有抑制和杀伤作用。艾叶还是一种应用广泛的食材，最典型的莫过于盛行在两广及湘、黔部分地区的民间美食一艾叶粑粑。艾叶既可以是药物，也可以是美食，这说明（  ）

①人们可以根据需要改变艾叶的特性从而使其具有不同的功能

②人们能够利用艾叶的客观属性来满足自身的不同需要

③艾叶在不同的生长阶段具有不同的特征从而呈现出不同的效用

④人们可以借助实践活动改变艾叶的状态使其得到合理利用

在化学反应前后，下列各项中①原子的数目，②分子的数目，③原子的种类④物质的组成⑤分子的种类，肯定不会改变的是____；肯定会改变的是____；可能改变也可能不变的是____。

读短文并按要求完成相应任务
    Today was the first day of the summer holiday．My friends and I went out together．We went swimming in the swimming pool．We swam for an hour．I did not swim well，but I enjoyed it very much．We had lunch in a fast—food restaurant．I had a sandwich and some orange juice．Alice had a hamburger．Jack had a lot of French fries and some cola．We went shopping in a supermarket．I bought a pink dress．Alice bought a pretty hat．Jack did not buy anything．
    We went home at 3 o'clock in the afternoon．We 、were tired，but we were happy．

水蒸汽通过红热的碳粉，发生的反应为：H₂O+C $\frac{\underset{\_}{高温}}{}$ X+H₂，则X为（   ）