请教~~~~~~~~~og10-119，讨论中没答案

119. Executives and federal officials say that the use of crack and cocaine is growing rapidly among work­ers, significantly compounding the effects of drug and alcohol abuse, which already are a cost to busi­ness of more than $100 billion a year.

(A)  significantly compounding the effects of drug and alcohol abuse, which already are a cost to business of

(B)   significantly compounding the effects of drug and alcohol abuse, which already cost busi­ness

(C)  significantly compounding the effects of drug and alcohol abuse, already with business costs of

(D)  significant in compounding the effects of drug and alcohol abuse, and already costing busi­ness

(E)   significant in compounding the effects of drug and alcohol abuse, and already costs business

Choice B, the best answer

请问which already cost busi­ness修饰谁？看了旧帖，大家说是the use of....，但是我怎么觉得不像呢，如果是the use，不应是是cost啊，is,应该costs啊？

请大家指教

通常情况下，which引导定于从句都是修饰离他最近的词，在这里就是abuse。

关于A of B which（或that）...，这个定于从句倒底是修饰A还是B要视情况而定，但通常都是修饰B

the effects of drug and alcohol abuse

A of B          A是中心词

修饰B也是可以的，要看句子意思，对吧