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.
48. 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.
on account of living on account of their living because it lives because of living being they live As used in choices A, B, and D, the phrases on account of and because of are unidiomatic; because, which appears in C and E, is preferable here since because can introduce a complete subordinate clause explaining the reason why the golden crab has not been fished extensively. B and E also produce agreement errors by using the plural pronouns their and they to refer to the singular noun crab. Choice D, like A, fails to provide a noun or pronoun to perform the action of living, but even with its the phrases would be more awkward and less clear than it lives. C, which uses because and it as the singular subject of a clause, is the best choice.
为什么说the phrases on account of and because of are unidiomatic?一直没想明白.