定语从句中when和where的用法IwillneverforgetthedaywhenIfirstmetyouontheseashore.Iwillneverforgetthedayswhich/thatwespenttogetherinXueyaoMiddleSchool.这两个句子中为什么分别用了不同的引导词?什么时

　　定语从句中when和where的用法

　　IwillneverforgetthedaywhenIfirstmetyouontheseashore.

　　Iwillneverforgetthedayswhich/thatwespenttogetherinXueyaoMiddleSchool.

　　这两个句子中为什么分别用了不同的引导词?什么时候用when,什么时候用which/that?

　　Thisisthehospitalwheremymotherworks.

　　Thisisthehospitalwhich/thatwevisitedthedaybeforeyesterday.

　　什么时候用where,什么时候用which/that?