essential 同时又要介词+引导词的定语从句怎么处理？

vicar

which只能引导nonessential定语从句 那么要介词+引导词的essential的定语从句怎么处理？
应该是the car with that we can fly is expensive.还是the car with which we can fly is expensive

5Day

后者。that不能引导介词开头的定语从句。