定语从句中 被动语态和完成被动语态的区别
一道题：
you may try some of the techniques______(outline)above.
这道题我个人很模糊
1.outlined
2.have been outlined
3.being outlined
这三个怎么区分呀
you may try some of the techniqueswhich are outlined above.
you may try some of the techniqueswhich have been outlined above.
怎么办 迷糊了~~~
求高手详细分析一下