定语从句中先行词为形容词最高级时,只用关系代词that.
1 .当先行词既有人又有物时,关系代词用that,不用which.
He asked about the factories and workers that he had visited.
2.当先行词有形容词最高级修饰时,关系代词用that,而不用which.
Guilin is one of the most beautiful cities that I have ever visited