再问OG103

103. Students in the metropolitan school district lack math skills to such a large degree as to make it difficult to absorb them into a city economy becoming ever more dependent on information-based industries.

(A)  lack math skills to such a large degree as to make it difficult to absorb them into a city economy becoming

(B)   lack math skills to a large enough degree that they will be difficult to absorb into a city's economy that becomes

(C)   lack of math skills is so large as to be difficult to absorb them into a city's economy that becomes

(D)  are lacking so much in math skills as to be difficult to absorb into a city's economy becoming

(E)   are so lacking in math skills that it will be difficult to absorb them into a city economy becoming

In A, lack is modified by a wordy and awkward construction, to such a large degree as to make it difficult to. B is similarly flawed, and to a large enough degree that is unidiomatic. C is ungrammatical because it uses lack as a noun rather than as a verb: the phrase beginning Students... becomes a dangling element, and them refers illogically to skills rather than students. Additionally, A, B, and C fail to use one or both of the "-ing" forms are lacking and becoming; these forms are preferable to lack and becomes in describing progressive and ongoing conditions. D uses the "-ing" forms, but so much... as to be difficult to absorb is an awkward and unidiomatic verbal modifier. Choice E is best.

Students in the metropolitan school district are （so lacking in math skills that it will be difficult to absorb them into a city economy） becoming ever more dependent on information-based industries。

后面的becoming到底是分词呢还是进行时态，如果是进行时态，有人见过如此奇怪的句子吗？

那怎么去解释OG中的这句话A, B, and C fail to use one or both of the "-ing" forms are lacking and becoming; these forms are preferable to lack and becomes in describing progressive and ongoing conditions.原文A中后面明显用的是becoming。

D有明显错误，so much。。。as to be