再问大全738，怎么理解它的时态

我笨，我努力

738.The Emperor Augustus, it appears, commissioned an idealized sculptured portrait, the features of which are so unrealistic as to constitute what one scholar calls an “artificial face.”

(A) so unrealistic as to constitute

(B) so unrealistic they constituted

(C) so unrealistic that they have constituted

(D) unrealistic enough so that they constitute（A）

(E) unrealistic enough so as to constitute

738, og-088, sec08-22

The verbs are and calls indicate that the sculpture is being viewed and judged in the present. Thus, neither the past tense verb constituted (in B) nor the present perfect verb have constituted (in C) is correct; both suggest that the statue’s features once constituted an artificial face but no longer do so. Also, B would be better if that were inserted after so unrealistic, although the omission of that is not ungrammatical. Choices D and E use unidiomatic constructions with enough: unrealistic enough to constitute would be idiomatic, but the use of enough is imprecise and awkward in this context. Choice A, which uses the clear, concise, and idiomatic construction so unrealistic as to constitute, is best。

我想知道，为什么解释说答案C的完成时和B的过去式用的不好？我不是很明白ETS对在这里的分析。请解答：）

如果排除时态问题，我觉得C和A从语法角度说都是没有错的，A优于C就是因为简练，可以这么理解吗？

请指点，谢谢

rt316

首先A的时态是可以接受的，表明所有的动作appears, are, constitute都发生在现在，而C改变了这个时态，将constitute这个动作放到了过去，所以认为C破坏了时态；当然从表达的角度来看，A和C的表达都是可以接受的。

M猫Fishoo

lz  黄色部分表明那里说no longer does so , 完成时不是一直持续到现在的影响, 而且有可能持续下去的意思吗?  为什么答案说以后就不了???   请教啊!!  请nn来解释一下啊~~