The golden crab of the Gulf of Mexico has not been fished commercially in great numbers, primarily on account of living at great depths-2,500 to 3,000 feet down.
The golden crab of the Gulf of Mexico has not been fished commercially in great numbers, primarily [on account of living] at great depth - 2,500 to 3,000 feet down.
A. on account of living
B. on account of their living
C. because it lives
D. because of living
E. being they live
答案是C。
D被排除的原因是, by OG, [because of living] is not the correct idiom. 为什么not correct?