Now,Tom,Name something that did not exist 25 years ago.怎么理解that
问题描述：
Now,Tom,Name something that did not exist 25 years ago.怎么理解that
答
that引导定从,修饰something,这儿只能用that不能用which.因为先行词something 为不定代词.
句意:现在汤姆给二十五年前不存在的某样东西命名.