GWD6-Q41

The greatest road system built in the America prior to the arrival of Christopher Columbus was the Incan highway,which,over 2,500 miles long and extending from northern Ecuador through Peru to Southern Chile.

B Columbus was the Incan highway,over 2,500 miles in length,and etended

E Columbus,the Incan highway was over 2,500 miles long,extending

B有什么错啊，不能用in length?

E不是重心转移了吗

The problem of B is the verb "extend" was used to reflect the road system.

It should be reflecting the Incar highway.

The "incar highway" is a tong wei yu, better choice.

为什么相同的问题总是有那么多人问呢。其实还是应该先搜索一下老帖子比较好。

我的理解是这样的(不过我没有搜索老帖子)

B的关键不是extend的发出者是谁，既然A=B, 你可以说B extend 当然也可以说A extend啦！关键是句子结构不合理:and extend 是和什么平行的呢，如果说是个was the Incan Highway平行，显然很别扭，我们通常不会在两个并列句子谓语一个是be动词，一个是实义动词的情况下并列并省略主语的，实在不行第二个主语还是会用代词补出来。常见的情况是都是be 动词或都是实义动词。

可能需要借助一些语感。

我能否说...B里面的表达客观事实不应该用was?

而E里面was over 2500 miles long，用了过去时...是不是说明了现在没有2500miles了？求解...

umm...还有我想说，B里面system是不可以extend，只有highway才能够extend这样子可以吗？

另外还有疑问...A里面为什么which前后都有逗号？