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.
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 解释说In (A) and (C), which introduces a restrictive clause. Some writers follow the convention that which can only be used for nonrestrictive clauses, but insistence on this rule is controversial。我不懂的是这里的意思是说一些作者认为which只能引导非限制行从句,但我们以前学的不是which可以引导从句什么的吗?