帮忙分析一道SC题

For the best extraction of the flavor of saffron threads, it should be soaked in liquid after being pounded with a mortar and pestle.

(A) For the best extraction of the flavor of saffron threads, it should be soaked in liquid after being pounded

(B) To best extract their flavor, saffron threads should be soaked in liquid after pounding

(C) The best way to extract the flavor from saffron threads is soaking them in liquid after being pounded

(D) The best way to extract the flavor from saffron threads is to soak them in liquid after pounding them

(E) The flavor of saffron threads can best be extracted by soaking it in liquid after pounding it

答案是D

这是机经题?不是应该发到专区吗

楼主有什么问题呢？

不定式表目的

(A) For the best extraction of the flavor of saffron threads, it should be soaked in liquid after being pounded

- "best extraction" is not clear here. "saffron threads" is plural so "it" is incorrect.

(B) To best extract their flavor, saffron threads should be soaked in liquid after pounding 
- the usage of "their" is unclear here.

(C) The best way to extract the flavor from saffron threads is soaking them in liquid after being pounded
- "to" is preferred here. "being pounded" is not correct.

(D) The best way to extract the flavor from saffron threads is to soak them in liquid after pounding them
CORRECT.

(E) The flavor of saffron threads can best be extracted by soaking it in liquid after pounding it

"it" has no clear referent here. Also saffron threads are plural so "pounding it" wouldn't be correct anyway.