The study period covered the past 20 years.

该研究涵盖了过去20年。

Sadly, the data also showed face-to-face socializing and sports activity had declined over the period covered by the survey.

遗憾的是，数据还显示， 在调查期间， 面对面的社交活动和体育活动有所减少。

The period covered by the 14th Five-Year Plan will be the first five years in which we embark on a new journey to build China into a modern socialist country in all respects.

" 十四五" 时期是开启全面建设社会主义现代化国家新征程的第一个五年。