have been done 和 have been doing剑桥中级英语语法里面有一个单元，给了一个例句：They have been married for 20 years.用了have been done这个形式，为什么不是They have been marring for 20 years?或者They have married for 20 year.而用了被动语态have been done，非常疑惑
问题描述：
have been done 和 have been doing
剑桥中级英语语法里面有一个单元，给了一个例句：They have been married for 20 years.用了have been done这个形式，为什么不是They have been marring for 20 years?或者They have married for 20 year.而用了被动语态have been done，非常疑惑
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