This is the pen with which I write.其中with+which能不能改成关系副词.就像This is the pen where I write.

with+which不能改成关系副词,
关系副词有: when, where , why ,改成哪一个都不合适.

This is the pen that I write.

This is the pen with which I write.
其中with+which不能改成关系副词.因为with which write = write with which/the pen.