一个没讨论过的选项 GWD-4-1 谢谢

古韵

The Acoma and Hopi are probably the two oldest surviving Pueblo communities, both dating back at least a thousand years.

 

 

1. both dating
           
2. both of which have dated
           
3. and each has dated
           
4. and each one dating
5. each one of which date

请问各路牛人B错在哪？谢谢不吝赐教！！！

songlovegt

both 和 which 重复，都可指代 communities
此外完成时没有必要

古韵

Thank you for your attention but I don't quite agree with you at this point.

In the first place, it is not rare to find:

     pl.noune, each/both of which...

In addition, other examples abound in GWD by using "have dated..."．

Again, sincere thanks for your prompt reply  

Open to discussion 

songlovegt

I agree with you that it's quite normal to use 'each/both of which' in informal writing. GMAC, however, doesn't think it's correct. You may review og first to get some ideas about GMAT grammar rules.