There are occasions _______________ one must yield. （屈服） Beijing is the place _______________ I was born.　 Is this the reason _____________ he refused our offer?　

when (=on which)

where (=in which)

why (=for which)

注意：先行词虽然是时间或地点，但若在定语从句中作主语或宾语时，要用关系代词。