they have been collecting stamps for 10 years在 collecting stamps下画线了 对画线部分进行提问( ) have they ( )( )for 10 years?

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/30 17:50:05
they have been collecting stamps for 10 years在 collecting stamps下画线了 对画线部分进行提问(  ) have they (  )(  )for 10 years?

they have been collecting stamps for 10 years在 collecting stamps下画线了 对画线部分进行提问( ) have they ( )( )for 10 years?
they have been collecting stamps for 10 years
在 collecting stamps下画线了 对画线部分进行提问
( ) have they ( )( )for 10 years?

they have been collecting stamps for 10 years在 collecting stamps下画线了 对画线部分进行提问( ) have they ( )( )for 10 years?
What have they been doing for 10 years?