英语中,引导非限制性定语从句的which前面可以加副词或介词短语吗?请高手举各举一例说明,

不能加副词,只能加介词,不是介词短语,可以是短语介词.如：Beijing, in which I worked five years ago, is the capital of Chian. They came to a farm house, in front of which sat a small boy.