请教一题

Proponents of artificial intellgence say they will be able to make computer that can understand English and other human languages,recoginze object,and reason as an expert does--computers that will be used to diangonse equipment breakdowns,deciding whether to authorize a loan,or other perposes such as these.

a as an expert does--computers that will be used to diangonse equipment breakdowns,deciding whether to authorize a loan,or other purposes such as these.

b as an expert does,which may be used for purpose such as diangonsing equipment breakdowns,deciding whether to authorize a loan

c like  an expert --computers that will be used for such purposes as diangonsing equipment breakdowns,or deciding whether to authorize a loan

上课的时候，老师说，Ａ错在these单独出现，但是这里不是已经举例了一些purpose了阿,有指代的对象阿，为什么错呢？

B错在，which没指代对象，但是原文不是已经说了computer了吗？有指代的对象阿？

mm刚起步吧！~~~

1、these/that等作为代词单独出现是错误的，these后面必须有名词，比如说：such as these purpose这样的表达才符合GMAT语法。

2、which的作用是就近指代前面的名词，as an expert does,which may be used 这里which前面是动词does无法指代。

还有A和B的as an expert does也是错误的，虽然as...可以表达比较，但是这里的比较对象出现了三个动词understand和understand和reason，does在这里究竟这代哪个动词就产生了问题，所以这种情况下最好用like+n的形式表示比较。

超级感谢就醉一生，解释的好清晰哦，很受用的说，我会继续加油的！