应该用that,因为visit动词后面宾语就是the park（用that代替）,不是做状语（状语的话,就要用where）,是做宾语（that=the park,做visit的宾语,用that或which）求分析句子成分。。This is the park. I want to visit it.This is the park ______I want to visit.This-主语 is-谓语动词 the park-表语. I -主语want-谓语动词 to visit-不定式做宾语 it-动词visit的宾语.This is the park---主句 ___that或which---关系代词引导定语从句___I want to visit---定语从句.