高一英语(Unit 1):同义句转换：Scientists have made great progress in the research on
问题描述：
高一英语(Unit 1):同义句转换：Scientists have made great progress in the research on
同义句转换:Scientists have made great progress in the research on the medicine but there is still a long way to go.
The medicine ____ ____ greatly ____ by scientists but there is still a long way to go.
答
The medicine _has_ _been_ greatly _improved_ by scientists but there is still a long way to go.improve有被动语态吗？有啊，及物动词都有被动语态的！