求助大全985，

wjjjojo

985  Those who have visited the Grand Canyon have typically seen layers of sediment in the gaping canyon, with different colors that mark the passage of time like the rings in a tree trunk.

(A) seen layers of sediment in the gaping canyon, with different colors that mark

(B) see layers of sediment in the gaping canyon, whose different colors mark

(C) been seeing layers of sediment in the gaping canyon, whose different colors are markers of

(D) been able to see layers of sediment in the gaping canyon, with different colors marking

(E) seen layers of sediment in the gaping canyon, marking by different colors 

答案 d 我选 a

Be able to 不是不可随意增减吗。再说把that 从句改为doing 也是不合理的， 麻烦nn们帮看下，谢谢鸟！！！

wjjjojo

又没人理，我自己顶

期待蔚蓝

Kaplan gmat 800上答案是A