I hate _ when people talk with their mouths full.

翻译：我讨 厌人们一边嘴里面满是食物一边交谈的时候.
语法规定如下：如果是表示爱憎类的动词如：like/love/hate/dislike 或 appreciate,rely on和see to等其后加宾语从句时,此时一般先用it做其形式宾语,其后再接that/when等引导的宾语从句.
再如：I like it when spring comes and everything comes to life.
Don't rely on it that he will help you.