100．Proponents of artificial intelligence say they will be able to make computers that can understand English and other human languages，recognize objects，and reason as an expert does--computers that will be used to diagnose equipment breakdowns, deciding whether to authorize a loan，or other purposes such as these． (A) as an expert does-computers that will be used to diagnose equipment breakdowns，deciding whether to authorize a loan，or other purposes such as these (B) as an expert does，which may be used for purposes such as diagnosing equipment breakdowns or deciding whether to authorize a loan (C) like an expert-computers that will be used for such purposes as diagnosing equipment breakdowns or deciding whether to authorize a loan (D) like an expert，the use of which would be for purposes like the diagnosis of equipment breakdowns or the decision whether or not a loan should be authorized (E) like an expert，to be used to diagnose equipment breakdowns，deciding whether to authorize a loan or not，or the like
C is correct.
我的问题是: 1. C中“——”起解释说明的作用，相当于定语从句,既然是定语从句,那为什么不是like an expert-computers will be used for ..., 而用that从句来修饰computers呢? 2.原文抽出主干为：they will be able to make computers that can understand...,recognize..., and reason like an expert --computers that will..., computers that will 又好象是同位语,是谁的同位语呢?前边的compurers吗?自己做自己的同位语吗? 翻看了以前所有的讨论,还是不明白.请大家帮帮忙!!!谢谢! | 
