it// may be// how hard you perceive that it will be to identify the cue// that mediates(意为“促成、导致”) how much mental effort is used to monitor for it(就是the cue)是个it强调句.
how hard// you perceive that// it will be// to identify the cue是how引导的表语从句,其中you perceive that是插入语,how hard it will be to identify the cue才是一体结构.
it(形式主语) has also been argued(谓语) that it may be how hard ...to monitor for it(真正主语)
翻译:与此相关,还有一种争论是,有可能你观察到识别线索有多大的困难,你就会动用多大的脑力来对之监测.
——【译苦思甜】团队成员荣誉回答