A Forty-Year Study on Hypertension的用法和样例：
- Forty years ago, teachers were on a pedestal.
- However, during the course of forty years studies, there were still many problems in IRT studies, such as shortage of theory logics, shortage of questions and even shortage of Chinese theories.
- Linguistics is a branch of study on human language.
- He reigned over the country for forty years.
- Roof Turf Building: A Study on Thymus serpyllum L.