prep2-67 比较对象

67.        (28020-!-item-!-188;#058&003766)

A pair of architects in Britain, who say that giant arches, bridges, and walls made of artificial bone could be easier to design and build than conventional structures, and already designed a number of structures, including a bridge, for showing how their idea would work.

(A) build than conventional structures, and already designed a number of structures, including a bridge, for showing

(B) build than conventional structures, and they have already designed a number of structures, which includes a bridge, to show

(C) build than conventional structures, have already designed a number of structures, including a bridge, to show

(D) also to build than conventional structures, already designed a number of structures, including a bridge, which shows

(E) to build than with conventional structures, have already designed a number of structures, including a bridge, which shows

key: C 这里比较对象是giant arches, bridges, and walls  和conventional structures吗，感觉意思不对等阿？

对等的，giant arches, bridges, and walls made of artificial bone和conventional structures的比较。

一个是人造骨架的建筑，一个是传统结构的建筑。