987-985 谢谢

fern

1.                             ?987-985 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.fficeffice" />

(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（D）

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

为什么要用been able to?

with different colors marking而不用with different colors that mark除了简洁还有没有什么原因?