further farther
further%4:02:02:: farther%4:02:02::
to or at a greater extent or degree or a more advanced stage (`further' is used more often than `farther' in this abstract sense)
further complicated by uncertainty about the future let's not discuss it further nothing could be further from the truth they are further along in their research than we expected the application of the law was extended farther he is going no farther in his studies