A is farther from B than C is.A到B的距离,大于C到B的距离.
A is farther from B than C is.= A is farther from B than C is from B
若将原句中的is去掉,变成A is farther from B than C 个人认为不会出现语病,只是难于理解点
A is farther from B than from C 意思发生了变化,变成了A到B的距离.大于A到C的距离
A is farther from B than from C=A is farther from B than A is from C根据你的回答，第（3）问，不会出现语病，那变成什么意思了？A is farther from B than C和A is farther from B than C is.是同样的意思，都是 A到B的距离，大于C到B的距离。