改进

improve; ameliorate; enhance; refine; better; upgrade; reform; perfect; advance; optimize; make improvements to; make better; progress; bolster; improvement; amelioration; enhancement; betterment; modification; reformation; pickup; refinement; upswing; improved; enhanced; on the mend

改善

improve; ameliorate; better; enhance; upgrade; refine; rectify; reform; elevate; optimize; enrich; advance; boost; uplift; perfect; polish up; make better; make improvements to; improvement; amelioration; betterment; enhancement; upward