既能用where又能用in which的情況
引導定語從句，在定語從句中作地點狀語，從句與先行詞的搭配缺少介詞in時，既能用where又能用in which。
（1）This is the house where/in which he used to live.
這是他過去住的房子。
�。�2）The old school has now turned into a large modern factory where/in which a lot of coulour TV sets are produced every year.
這所舊學�，F(xiàn)在已變成一個大型的現(xiàn)代化工廠，每年生產(chǎn)許多彩色電視機。
只用in which不用where的情況
1.引導定語從句，但在定語從句中不作地點狀語，而是作方式狀語時，只用in which，不用where。
�。�1）This is the best way in which we can do the work well.
這是我們把工作做好的最好辦法。
2.引導定語從句，介詞in與定語從句中某些詞語構成固定搭配時，只用in which不用where。
�。�1）He left his work in which he had been very successful.
他離開了他非常成功的工作。