问题 填空题

请你参与某学习小组的探究活动,并回答相关问题:

小丽发现盛水的铁锅在与水面接触的部位最易生锈;小茜发现自己的铜制眼框表面出现了绿色的铜锈;小玲发现苹果切开不久,果肉上会产生一层咖啡色物质,好象生了“锈”一般.

提出问题:这三种物质“生锈”的原因是什么?

收集证据:(1)回忆已有知识:铁生锈的条件是______.

查阅有关资料:“铜锈”主要成分是Cu2(OH)2CO3(俗称铜绿);苹果“生锈”是果肉里的物质(酚和酶)与空气中的氧气发生了一系列的反应,生成咖啡色的物质.碱石灰能吸水.

实验探究:将四小块铜片分别按下图所示放置一个月,观察现象如下:

实验装置 

 

 

实验现象 铜丝不生锈  铜丝不生锈 铜丝不生锈 铜丝生锈且水面附近锈蚀最严重
由实验可知,铜生锈是铜与水、______、______等物质共同作用的结果.

______经过交流讨论,三位同学认为这些物质“生锈”除了可能与水有关外,还可能都与______填物质名称)有关.

反思与应用:利用所得结论填空:

(1)写出一种防止铁或铜等金属制品生锈的具体方法______;

(2)请你提出一条延长食品保质期的建议______.

答案

(1)铁生锈的条件是:与氧气和水同时接触.

由实验现象可知,铜在氧气、水、二氧化碳同时存在的情况下最容易生锈.故填:氧气;二氧化碳.

物质“生锈”除了可能与水有关外,还可能都与氧气有关.故填:氧气.

反思与应用:(1)防止铁或铜等金属制品生锈的具体方法是:保持金属制品表面的洁净和干燥(或表面镀上保护膜等).

(2)延长食品保质期的建议:将食品进行真空包装等.

阅读理解

The Chinese are very generous when it comes to educating their children. Some parents send their children to the best schools or even abroad to England, the US or Australia, regardless of how much this costs. Many also want their children to take extra-curriculum activities (课外活动) where they either learn a musical instrument or ballet, or other classes that will give them a better start in life. The Chinese believe that the more expensive an education is, the better it is, so parents often spend a large amount of money on education. Even poor parents manage to buy a computer for their son or daughter.

In fact, most parents fail to see that the best education they can give their children is usually very cheap. Parents can see that their children’s skills are different; they will usually be skilled in some areas while poor in others. However, they fail to realize that today’s children are lack (缺乏) of self-respect and self-confidence.

The problem is that parents are only educating their children on how to take exams and how to study effectively. They are not teaching them the most important skills they need. They do not teach them to be confident, happy and clever.

Parents can help achieve this by teaching their children practical skills like cooking, sewing and other housework.

Teaching a child to cook will improve many of the skills that he will need later in life. Cooking demands patience and time. It is an enjoyable but difficult experience. A good cook always tries to improve his cooking, so he will learn to work hard and finish his job step by step. The result, a well--cooked dinner, will give a child a lot of satisfaction and confidence. All these will help the children step to success in the future.

An old machine such as a broken radio or TV set that you give your child as a toy may make him curious and arouse(唤醒) his interest. If he will spend hours looking at it, and try to mend it; your child might become an engineer when he grows up. Such activities do more than teaching a child to read a book. They teach them to think and to use their minds. This is much more important than learning by reading a book.

1.Is the writer satisfied with the Chinese parents’ ideas of educating their children?

2. Put the underlined sentence “the more expensive an education is, the better it is” into Chinese.

3.What are the children lack of today?

4. How is the experience of cooking according to the fifth paragraph?

5.What does the underlined word “They” refer to(所指的是) in the last paragraph?

单项选择题