"FARTHER" and "FURTHER"

"Farther" refers to physical distance. "Further" relates to metaphorical or non-physical distance. Ex.: The park is farther than I thought. We need to look further into this issue.

"BREATHE" and "BREATH"

"Breathe" means to inhale and exhale. "Breath" refers to a single inhalation or exhalation. Ex.: Remember to breathe deeply and relax. She took a deep breath before diving.