the informal group is formed spontaneously , so it has its distinctive feature different from formal group.
非正式群体是学生自发形成的,因而具有不同于正式群体的特点。
the informal group could n ' t be replaced by the formal group in satisfying the needs of the students
在满足学生需要方面,非正式群体起到了正式群体难以替代的作用。
Members of the informal group of rich nations agreed last July to cancel all of the $214 million owed by Haiti.
这一非正式富裕国家组织去年七月同意免除海地14亿美元的负债。