求解释一道SAT语法题：Many alcoholics attempt to conceal their problem from their fellow workers,( but invariablyfailing to keep their secret.)A.but invariablyfailing to keep their secret.B.but they invariably fail to keep their secret.D.who invariably fail to keep their secret.
问题描述：
求解释一道SAT语法题：
Many alcoholics attempt to conceal their problem from their fellow workers,( but invariablyfailing to keep their secret.)
A.but invariablyfailing to keep their secret.
B.but they invariably fail to keep their secret.
D.who invariably fail to keep their secret.
答
b 许多酒鬼试图隐藏他们的问题不被他们的同事知道，但总是无法保持他们的秘密。)
答
赞成B。
答
平行结构.sd do ,but do D.指代错误
答
A, 平行结构～没有指代误解的问题