Trees were being planted here this time last year.变过去进行时主动语态快
问题描述：
Trees were being planted here this time last year.变过去进行时主动语态
快
答
we/they/people were planting trees here this time last year.
主语没有明确给出，只要是人就行
答
people were planting trees here this time last year.
答
They were planting trees here this time last year.