这是错句
关系代词that错误 应该 用in which 或where引导定从
因为后面从句完整 无需代词.
In a world in which the rate of technological and social change accelerates frighteningly,是地点状语
在这个状语中 in which 引导 定语从句 并在从句中 作状语 .定从 修饰a world
在这个定从中 the rate of technological and social change是定从中的主语
accelerates frighteningly是定从中的谓语,
change itself 是主句主语
often seems to be the only constant是主句谓语.