In Britain, "pig" refers to any member of the class of domestic swine, but the United States uses the term when referring only to younger swine not yet ready for market and weighing less than 82 kilograms (180 pounds).
(A) the United States uses the term when referring
(B) the United States term refers
(C) in the United States the term refers
(D) in the United States they use the term as it refers
(E) it is used in the United States when referring
"pig" refers to any member..
but the United States uses the term
when referring only to younger swine...
A. In Britain 应该是和but in the united states 平行；排除；
C. In britain, but in the united states; pig refers to ...,but the term refers to...平行
E. When refering改变了句子重心：原文想要表达的是refer作谓语，而不是做修饰；
When refering 表达不简洁