(1) 从句部分 other vistors seldom go 缺少地点,所以用where = to which
which 指代前面先行词school,museums,and some other places,
所以 other vistors seldom go to the school,museums and some other palces
to 是与go 连用的
（2）He is the only one of the students who has got very good marks in the martch.他是学生中唯一一个在比赛中取得好成绩的.定语从句不是修饰的students,而是修饰的the only one,也就是说who指代the only one 所以用has
(3) He is one of the students who have got very good marks in the march.他是比赛中取得好绩的学生中的一个.定语从句修饰the students,所以who 指代the students,用have
(4) from where 其实是指 from the place where he stood ,from 前面有逗号,说明是非限制性定语从句,关系词where 指代主句的全部或部分事实,主句交代了他站在什么地方,从句说从他所站的地方,他可以看到.
He stood at the windows from which he could see what was happening.