11. All these issues have been ____ researched in recent years.
A、intensively
B、extensively
C、intension
D、extendedly
11. All these issues have been ____ researched in recent ye - Unit 2 Childhood memories - 《新标准大学英语》综合教程(第三册)(第四次开课) - 重庆高校在线开放课程平台 | 大学网课搜题引擎