标题: OG12-10 [打印本页] 作者: qiuhua01234567 时间: 2012-4-24 19:50 标题: OG12-10 10.Carnivorous mammals can endure what would otherwise be lethal levels of body heat because they have a heat-exchange network which kept the brain from getting too hot.
(A) which kept
(B) that keeps
(C) which has kept
(D) that has been keeping
(E) having kept CMistaken shift in tense: In this sentence the present tense expresses a timeless general principle; in contrast,has kept indicates a more definite context and time period and suggests that the heat-exchange network may no longer have this effect. 这句话里OG想说明什么东西？跪求指导。作者: mslancaster 时间: 2012-4-24 19:57
C选项错误的改变了时态。
一般现在时是描述一个客观现实的，这个客观现实不会随时间的变化而改变。 然而， has kept作为完成时，规定了时间范围并且说明这个热交换系统到此刻为止便不再拥有从句之后内容所解释的功能。