OG-082

82. In contrast to large steel plants that take iron ore through all the steps needed to produce several different kinds of steel, processing steel scrap into a specialized group of products has enabled small mills to put capital into new technology and remain economically viable.

(A)              processing steel scrap into a specialized group of products has enabled small mills to put capital into new technology and remain

(B)              processing steel scrap into a specialized group of products has enabled small mills to put capital into new technology, remaining

(C)              the processing of steel scrap into a specialized group of products has enabled small mills to put capital into new technology, remaining

(D)              small mills, by processing steel scrap into a specialized group of products, have been able to put capital into new technology and remain

(E)small mills, by processing steel scrap into a specialized group of products, have been able to put capital into new technology and remained

remain这个词作为"保持"解释是不是不可以有完成时态?象E中的错误.

请NN确认一下.

这样就在判断答案时起码又多了一个标准.