刚看到别人的帖子里面一道题,7.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. 这道题原句划线部分which kept应该改成that keeps。可见that在定语从句中做连词当充当从句中主语的时候是不可以省略的。现在仅剩的问题是,当充当宾语时,是必须省略还是省略不省略都行?请多多指教!