阅读下面一则学校海报，选择正确答案。

SCHOOL EVENTS

OPEN DAY（开放日）：

AUGUST 16th, 2012 9:00 ~ 12:00 a.m.

All parents can come to our school, have a cup of coffee, and meet our teachers and other parents.

Parents can go to the classrooms of 12 ~ 15 years old, have a talk with the principal (校长), have a look at the clubs and ask any questions.

All requirements（要求）for a happy school are welcome.

Lunchtime: 11:30 ~ 12:00 a.m.

Please go to Room 305 for lunch.

All parents are welcome. Please contact (联系) us.

Contact: Melodie Lezar, the principal

TEL: 021- 4615998

E-mail: disapark@ telkoms.a.net

School: Goodwin Middle School

内蒙古自治区从东往西的植被变化大致表现为（　　）

对联是中华文化所特有的表达方式，有时也承载着历史的信息。以下是某同学收集的新中国成立以来的给付对联：

对联一：万里河山归人民，五亿群众庆新生

对联二：走计划建设道路，做三大改造先锋

对联三：过年储米十余担，压岁存款上千元

对联四：杂居聚居遵民意，五区人民得自治

请回答：

由不同的组织按照一定的次序结合在一起构成的行使一定功能的结构叫做____．