问题 单项选择题

下列关于赋值运算符“=”重载的叙述中,正确的是

A.赋值运算符只能作为类的成员函数重载

B.默认的赋值运算符实现了“深层复制”功能

C.重载的赋值运算符函数有两个本类对象作为形参

D.如果己经定义了复制(拷贝)构造函数,就不能重载赋值运算符

答案

参考答案:A

实验题

小明同学在“金属拓展阅读”活动中了解到:金属钠在常温下与水剧烈反应能生成一种可燃性气体。教师结合小明已有知识设计了下图所示装置进行实验。

【小资料】金属钠一般存放在煤油中或用石蜡封存,煤油的密度为0.8g/mL。

(1)问题:采取上述保存金属钠的方法中,煤油或石蜡的作用是              

(2)实验过程

 操作现象及解释
打开止水夹a及分液漏斗活塞,待液体充满大试管后,关闭止水夹a及分液漏斗活塞。液体分层,钠熔成银白色小球,在液体分层的界面上方跳动,产生大量气泡,下层溶液变成红色,并逐渐被压入B中。金属钠的物理性质(写出一点即可)                
打开止水夹b,待B中部分溶液进入C中,迅速关闭止水夹b。 

反应的化学方程式为                 

打开止水夹c。                                      

        溶液红色消失。

反应的化学方程式为                    

将燃着的木条伸到导管尖嘴处,打开止水夹a;

在火焰上方罩一个干冷的烧杯。

气体燃烧,产生淡蓝色火焰

烧杯内壁有无色液滴生成,A中气体为氢气。

(3)反思分析

金属钠与水反应的化学方程式为                           

反应结束,C中溶液的溶质是(指示剂除外,写出所有可能)                       

阅读理解

Teenagers at one German school are learning how to achieve happiness alongside other traditional subjects such as math and languages.

The class sit in a circle with their eyes shut and they count from one to ten: someone starts, the next voice comes from the far right, a third from the other side.

The aim of the game is to listen for an opportunity to shout out the number without clashing (冲突) with another voice or leaving a pause. On the first try, most of the young Germans try to be first, while a few are too shy to join in, but by the fifth time round, they develop a rhythm. The message: give other people space but also confidently claim your own. This is a requirement for social well-being.

The Willy Hellpach School in Heidelberg is the first in the nation to develop a happiness course. It is intended for students preparing for university entrance exams.

"The course isn't there to make you happy," Ernst Fritz -Schubert, the school principal, warned pupils, "but rather to help you discover the ways to become happy."

Cooking a meal together is one of the class exercises. Improving body language under the guidance of two professional actresses is another.

The course is taught for three periods a week. Despite the happy subject, the pupils themselves insist it is no laughing matter.

"In the first period, we had to each say something positive about another member of the class and about ourselves. No laughing at people." said Fanny, 17.

Research by the school shows it is not the first to start happiness classes: they also exist at some U. S. universities, mainly based on positive thinking, using findings from studies of depression.

小题1:What's the writing purpose of this passage?

A.To help students struggle against being sad.

B.To describe all the traditional courses.

C.To arouse the readers' interest in happiness.

D.To introduce the happiness course.小题2:The game intended for the students in the 2nd paragraph is mainly to _________.

A.try their best to get opportunities for themselves

B.practice how to speak in front of people

C.equip them with required social skills

D.confidently speak out one's opinions小题3:According to the passage, the happiness course is _________.

A.to help students discover the ways to happiness

B.to make all the students happy all the time

C.required to be taken by the first year students

D.created by the Willy Hellpach School小题4:It can be inferred from the passage that _________.

A.the students can certainly become happy after the course

B.the students just took the course as a laughing matter

C.the students' self'-respect can also improve happiness

D.the students waste time learning something without value