The Sheffield investigation, which involved sixteen primary schools and seven secondary schools, found that most schools succeeded in reducing bullying.
谢菲尔德的调查涉及16所小学和7所中学，结果发现大多数学校都成功地减少了校园欺凌行为。
2
In this research study, I together with the students of secondary school students were deep into the subject Starchaser investigation.
在这次课题研究性学习中，我与同学们一齐对中学生追星题目进行了深进调查。
3
Researchers usually start their investigation by examining secondary data to see whether their problem can be partly or wholly solved without collecting costly primary data.