状语从句,是从句的形式做状语,修饰的是主句的谓语动词
而定语从句,是从句的形式做定语,修饰的是主句中的某个名词、代词
区分的话,简单的说,从句修饰主句谓语的是状语从句
从句修饰主句中的名词性成分的,是定语从句.
如：I still remember the day（这里是表示时间一天） when she 1st came to school.(定语从句,修饰先行词the day)
I stopped eating（） when she came in.(状语从句,修饰stopped,)
I can't think of a single search where a.board has not instrcuted me to look at sitting CEOs first. 句中where 是修饰 a single search
主要具体看翻译