The chairman_________all the people to c

任务型阅读（本题有5小题，每小题1分，共5分）

每一幅新闻图片的背后都蕴藏着一个故事。配对新闻内容及图片，请把A、B、C、D、E字母填入相对应的题项空格中。

1.                        2.                       3.               

4.                       5.               

A. China's Li Na hits a shot during her first round match against Christina McHale of the US at the Sydney International tennis tournament Jan 7, 2013.

B. A teacher leads a class of students doing their exercises between classes in a classroom instead of outdoors, at a primary school in the city of Jinan on Jan 14.

C. An artist performs Beijing Opera to celebrate the upcoming Chinese Spring Festival in Cairo, capital of Egypt, Jan 28, 2013.

D. A child gets a haircut at a barber shop in Huaibei, Anhui province, March 13, 2013. Many Chinese who follow tradition choose to have their hair cut on Feb 2 on the lunar calendar.

E. Students carry trees to be planted in a school in Zhumadian city, Henan province, March 11, 2013.

铅蓄电池工作时，总的反应式为：Pb+PbO₂+2H₂SO₄ =2PbSO₄ +2H₂O，由此可以判断：

(1)原电池的电极材料：正极：____________，负极：_____________

(2)两电极的电极反应式：正极：________________， 负极：________________。

在C++中，编译系统自动为一个类生成默认构造函数的条件是

A．该类没有定义任何有参构造函数

B．该类没有定义任何无参构造函数

C．该类没有定义任何构造函数

D．该类没有定义任何成员函数

大型机床，安装前除对基础检查验收外，一般还要对基础进（）处理。

A.7.8

B.8.8

C.10.8

D.9.8

射流式液动锤利用什么原理配流？