Do you still remember the days (when) we spent together last summer?Yeah,I will never forget the days (that) we played together.为什么一处用when,另一处用that.动词forget 和remember是互为反义词，他们有不同之处吗？请指教

Question

Do you still remember the days (when) we spent together last summer?Yeah,I will never forget the days (that) we played together.为什么一处用when,另一处用that.
动词forget 和remember是互为反义词，他们有不同之处吗？请指教，

Answer 1

Do you still remember the days ---- we spent together last summer?这个句子中的关系词要用关系代词that或which,因为在定语从句中缺少的是动词spend的宾语；
Yeah,I will never forget the days ---- we played togethe中的关系词要用关系副词when,因为在定语从句中,缺少的是动词play的状语.