新prep-232，求助！！！！！

232.     (32872-!-item-!-188;#058&006915)     (TTGWD4-Q1)

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

A. both dating

B. both of which have dated

C. and each has dated

D. and each one dating

E. each one of which date

尝试着说一下。。。CDE肯定不对，each一般用于独立主格结构，不需要and引导，直接each+名词+修饰语（分词形容词那些）。B的话，原文没有标志用完成时的词，比如during那些的，根据自己做了这么长时间的语法，觉得用完成时的时候一定要看有没时间标志词，不能乱用 

A是后置定语，修饰那两个communitues。

不知道能不能帮到你

顶起来

date 用现在完成时很合理啊

Rock samples taken from the remains of an asteroid about twice the size of the 6-mile-wide asteroid that eradicated the dinosaurs has been dated to be 3.47 billion years old and thus is evidence of the earliest known asteroid impact on Earth.

A. has been dated to be 3.47 billion years old and thus is

B. has been dated at 3.47 billion years old and thus

C. have been dated to be 3.47 billion years old and thus are

D. have been dated as being 3.47 billion years old and thus

E. have been dated at 3.47 billion years old and thus are

这个题也是PREP上的一道题，答案是E啦，不就是用了完成时态嘛？？？

求助ing

date at与date back不同，一般date back的时间是从现在算起，故谓语动词多用一般现在时。另外句里也没有任何含义表明要用完成时态。

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

A. both dating

B. both of which have dated

C. and each has dated

D. and each one dating

 D E选项可不可以认为是each 和one语义重复了呢 ？

each one没什么问题的。比如下面这个句子：

大全191:In the shark's jaws, many spare teeth lie in seemingly limitless reserve, each one ready to slide into the appropriate position whenever an active tooth is lost or worn down.

先指正一下2楼，each 独立主格不是 each+ 名词再+ 什么什么，而是each + doing/ done/ prep+n/ adj+prep+n/ n

再说我的一点看法，我也错了这道题，后来分析的时候突然觉得，我们经常用each doing独立主格，而这里both dating其实不就是它的变体么？！both,each在这里都是限定词。请NN指正！！