88. The Emperor Augustus, it appears, commissioned an idealized sculpture 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

136. Although schistosomiasis is not often fatal, it is so debilitating that it has become an economic drain on many developing countries.

(A) it is so debilitating that it has become an economic

(B) it is of such debilitation, it has become an economical

(C) so debilitating is it as to become an economic

(D) such is its debilitation, it becomes an economical（A）

(E) there is so much debilitation that it has become an economical

88题OG中对C的解释：the present perfect verb have constituted (in C) is NOT correct that suggests that the statue’s features once constituted an artificial face but no longer do so. C中的现在完成时表示该动作到现在为止已经完成了，不再延续，因而是错误的。
136题中对A的解释：是合乎习语的。为什么schistosomiasis 在A中用现在完成时表达它是一种经济实惠的排水物质，就可以用现在完成时，而不产生如88题中C的错误呢？

so that/so as to出了看逻辑主语一致和表语结构外还有其他区别吗?

观察的很细致. 我觉得两道题都是客观事实, 用现在完成时都不好. 那么为什么在OG136中用完成时就是正确的呢? 我觉得还有一点. 就是答案是比出来的. 如果没有别的答案对, 就选最好的.

关于so that/so as to我主要是通过逻辑主语来确定.